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Thanks for the wisdom. This entire experience has made me really miss that I no longer live across the street from the friendly neighbor HVAC dude who would fix stuff for us for a plate of cookies. Just heard that he's passed his contractor certifications so he can start his own business though, good for him.
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Aug 1, 2022 16:05
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His Divine Shadow posted:I noticed last winter that my heat recovery ventilation system was only 60% efficient but it should be more like 80%+. I finally took a look at the attic and yeah, I guess the answer is pretty plain, insufficient insulation around the ducts. I am buying more insulation and wrapping around the ducts soon. I've been wondering if I should dig away and wrap the insulation all around the ducts, or if I should like get bigger mats and lay them over the ducts so that they and the area around is covered like a blanket. Those rafters are intense. Is there a functional reason why your roof is so vaulted or is it just an aesthetic thing?
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Aug 1, 2022 16:08
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I never thought about it, can't be aesthetic since nobody sees them. Strength perhaps, snow weight and all that.
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Aug 1, 2022 16:26
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So this is just academic as I'm not going to replace my existing equipment, but I'm curious how you would size an HVAC system for the increasing temperatures in the south. This is mostly just me gathering information for my next house. Current home is 3400 sq ft, and I have 2 AC units. 2.5 ton system downstairs, 2 ton system upstairs. My house is 4 years old and relatively energy efficient. It's pretty clear the HVAC system was designed for a 95 degree summer, and I get that.. I'm outside the San Antonio area, and it's been over 100 degrees for pretty much the last 2 months, with some days hitting 105. The AC system can't maintain my setpoint of 71 degrees at that point. 3pm or so upstairs will get as hot as 75, and downstairs will get to 73 or 74. Those are worst case numbers. They systems are regularly serviced and in proper working order (charge is good, coils are clean, etc). This isn't a huge deal, I get that the system was sized for 95 degrees, and honestly indoor temps of 75 when it's 105 outside is nothing to complain about. Like I said, this is mostly academic. I know oversizing AC units is just as bad or even worse than undersizing them, and this year has been setting all time records as far as heat goes, but how would you design an HVAC system to have the capacity to deal with this? I'm guessing the answer is spending the money on one of those variable speed systems like a Carrier Infinity system that can run from 25% to 100% capacity and then sizing the system for 105 or even 110 instead of 95. It's not like things are going to get cooler on average.
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Aug 1, 2022 16:52
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Motronic posted:The problem I've found with Goodman is that they'll sell to anyone. That's what I expected when the Goodman vendor showed up today, but out of the 3 I saw, he was the most professional, knowledgeable, and thorough in the spec-ing of the system. I'm still waiting on Trane, but I'm assuming that's going to be 25% higher than what I have now. For a 2 stage furnace with variable speed drive, 2 stage AC, Lennox and Goodman showed up within a couple hundred bucks of each other, right at $11k. Even though Lennox is a "better" name, I'm leaning towards Goodman. Thoughts?
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Aug 1, 2022 16:54
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EVERYWHERE 
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meatpimp posted:That's what I expected when the Goodman vendor showed up today, but out of the 3 I saw, he was the most professional, knowledgeable, and thorough in the spec-ing of the system. If that contractor seemed to be the most on the ball I wouldn't turn up my nose at it. They could just be really good at their job and like the increased margins the Goodman units provide them.
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Aug 1, 2022 17:10
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I've had two Goodman heat pumps installed in the last two years so... I'm mostly happy with them. Both replaced original ~Y2K era builder-quality units; the first was an urgent replacement at my old house when the coil in the outside unit sprung a leak. I went with a mid-tier two-stage system there. Zero problems, much improved performance / much lower noise than the old system, and while I ended up selling the house before putting that system through a full summer, even at 90 degree average (average of high+low) days I was seeing a reduction of 20kWh on my daily usage. Current house I did a proactive replacement since the heat pump was original, I wanted to do it during the time of year when things wouldn't get too nasty outside, and I didn't want to be stuck with a hot house waiting on supply chain issues foreshadowing. Went with an Amana-branded fully-variable system. Worked perfectly again for months. Then in May we took a trip, and while we were gone our housesitters never mentioned the fact that they'd cranked the thermostat down and it never got to the set point despite running 24 hours nonstop. It took two weeks to get things finally fixed, largely because of parts availability. At first the system wouldn't spin up above 40%, and eventually it just quit altogether, with the compressor making all kinds of awful noises. The (fully warrantied) repair so far has been an entire new outside unit, and a new control board on the air handler. On top of that, the air handler control board is technically a temporary fix. The one that came in the air handler handles the variable stages on its own and works with typical 24VAC controls. The only control board they could get their hands on at that time requires a matching communicating thermostat. They were told "2-4 weeks" lead time on the "correct" control board in June and they're still getting that same answer now. I'm about to ask them if they can just leave this as a permanent setup since I think the communicating thermostat does a better job of varying the system versus actual load. I'm still happy with the unit and I don't doubt my HVAC company or their diagnostics work, which they went through with me in detail. I'm still trending out data for the summer but I think we're seeing more like a 40-50kWh daily usage drop from last summer for the same temperatures. I don't know that the system will ever pay for itself, but it is quiet.
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Aug 1, 2022 17:18
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So Amana and Goodman are now similar since they're both under the Daikin parent company umbrella? I haven't looked at Amana at all. Edit: Wow, they are exactly the same, other than "A" versus "G" as the leading letter of the part number. https://www.questargas.com/ForEmployees/qgcOperationsTraining/Furnaces/Goodman_GMVC96_Installation.pdf IOwnCalculus posted:The only control board they could get their hands on at that time requires a matching communicating thermostat. Is that the Honeywell RedLINK system? Thermostat named Prestige or VisionPro 8000? meatpimp fucked around with this message at 18:03 on Aug 1, 2022 |
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Aug 1, 2022 17:56
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The part of our A/C that's in our hallway is Goodman. Our big fan outside is American Standard. I think the repair guy said the fan was an R22 unit.
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Aug 1, 2022 18:12
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meatpimp posted:Even though Lennox is a "better" name, I'm leaning towards Goodman. Thoughts? It's all about 1.) install quality 2.) locally available parts/service. I'd 100% buy yet another standard goodman. I'd have to do some research on anything "fancy" (i.e. multi stage) to make sure these are parts that would be on a truck or at least local as opposed to moon parts (which absolutely seems to be happening to even the "good" brands, IOC certainly knows that).
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Aug 1, 2022 18:15
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meatpimp posted:Edit: Wow, they are exactly the same, other than "A" versus "G" as the leading letter of the part number. https://www.questargas.com/ForEmployees/qgcOperationsTraining/Furnaces/Goodman_GMVC96_Installation.pdf It is literally that, just part number and label differences. Technically I think my air handler has a Goodman sticker on it instead of Amana but they're all Daikin. The thermostat is branded as Comfortlink, but now that you gave me some search terms, yes, it appears to be Honeywell Prestige / Redlink. The thermostat I have on the wall right now has this exact touchscreen interface, in a slightly larger case. And yeah, HVAC is just another industry in supply-chain hell. We're friends with the owners of the HVAC company we used both times and they mentioned that in the before times, not only would the local Goodman supplier have the parts on hand, they'd also have staff available to get at the parts seven days a week. Right now the warehouse barely has anything, and they're only staffed enough to keep the warehouse open for banker's hours, which helped drag the repair time out longer. Really, the only fault I can put on Goodman here is that it took a few phone calls and videos before they'd acknowledge that "knocking like a Subaru" is not a normal operating mode for the compressor. They wouldn't authorize a swap on the whole outside unit initially because it was technically passing every other test they put it through.
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Aug 1, 2022 19:08
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MRC48B posted:almost nobody installs those for single family residential because they are extremely expensive for no payback. I wasn’t home today but my wife turned the bottom unit off and the upstairs worked way better. HVAC company has been called.
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Aug 1, 2022 21:39
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His Divine Shadow posted:I never thought about it, can't be aesthetic since nobody sees them. Strength perhaps, snow weight and all that. I meant aesthetic in terms of the roof pitch rather than the rafters themselves. But avoiding a critical accumulation of snow makes sense.
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Aug 1, 2022 23:01
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Motronic posted:The problem I've found with Goodman is that they'll sell to anyone. The rest of the brands - for better or worse - require an authorized dealer network that provides for some kind of competency in selection and installation, although it seems increasingly that it's still not enough. But at the very least it's an established HVAC company who can supply this equipment as opposed to the last refuge of plumbers and handymen doing HVAC: Goodman. Commercial/industrial/instituitional actually. That just means less goodmans, and more ancient tranes/carriers/other Name Brands that are ancient and been resurrected multiple times long after they should have been replaced. I've recently moved to the controls department though, There's no way my knees can take hauling Q tanks up 20ft ladders for the next 30 years.
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Aug 1, 2022 23:43
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H110Hawk posted:So I know that sqft to ton is not how you do it but Ya it's definitely oversized (arguably). In the Valley, most of these homes are mid 50's built, no insulation in the exterior walls, and originally single pane windows and no insulation in the attic. In the era of cheap power, the solution was to just put a giant AC unit on the roof. This house has since been upgraded to double-panes on the windows that get direct sun exposure. We'll be insulating the attic and adding radiant barrier, so we expect to need a lot less cooling power. As it stands, the unit runs for only a few minutes at a time, as its so overkill it can bring the whole home down a couple degrees in a few minutes. This is the primary issues right now, the temperature fluctuations are wild, and when the system is on, it blasts freezing air out of the vents--god forbid you stand in front of one. Qwijib0 posted:I would find the manuals for the "smart thermostat" compatible mode to see if it actually does what you want. My carrier greenspeed variable is also "compatible" but it turns it into a two stage. I have never seen a residential variable condenser/fan unit that has a published protocol spec to let a 3rd party take advantage of it. It might try and ramp up and down speed based on how long the cool call lasts but that's going to be a much different experience than a communicating thermostat Qwijib0 posted:the manual was linked at the bottom, and it is a variable speed compressor-- but you set it to a single speed at install. It appears to be designed as a single SKU for easy stocking. The installer will set the tonnage to 2,3,4 or 5, and at that point it's a single-speed unit. it only has an R, Y and C connection to the indoor components, so that's compressor on/off and a common wire only. That's what I'm trying to understand about the unit--it isn't a communicating unit (it's not even an option), but does advertise itself to be an inverter system that minimizes fluctuation (hence the fun graphic in the marketing brochure: https://cdn.gateway.acpro.com/documents/XSeries_FlyerHomeowner.pdf). I'm assuming it just does some voodoo by monitoring return air and exhaust air temperature? It's hard to verify what it's really doing.
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Aug 2, 2022 08:28
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5tons for 1400sqft? That seems like at least 2 tons too many. I would insist on someone doing a manual j. It seems like if you actually need 5 tons you should spend some money on insulation and sealing up, likely all of which would come from the reduced hvac size.
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Motronic posted:I'd 100% buy yet another standard goodman. Good to know. That says a lot. IOwnCalculus posted:It is literally that, just part number and label differences. Technically I think my air handler has a Goodman sticker on it instead of Amana but they're all Daikin. Yeah, I see supply chain nonsense, which doesn't reflect on Goodman, imo. Interesting, I'm leaning that direction.
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Aug 2, 2022 13:04
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the poi posted:As it stands, the unit runs for only a few minutes at a time, as its so overkill it can bring the whole home down a couple degrees in a few minutes. This is the primary issues right now, the temperature fluctuations are wild, and when the system is on, it blasts freezing air out of the vents--god forbid you stand in front of one. I'm guessing it's less of an issue in your area due to low humidity but this is bad, cycling like that is probably not very efficient, wears out your contactor and motor (etc...) Faster, and means you'll be more likely to have moisture issues since it'll never properly stay running long enough to dehumidify the space. Modern variable speed units are less likely to run into these issues when oversized, but have supply chain issues.
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Aug 2, 2022 17:30
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Still waiting on a quote from the Trane vendor. 
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Aug 3, 2022 22:23
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meatpimp posted:Still waiting on a quote from the Trane vendor. It's hard to shop a Trane.
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Aug 3, 2022 22:30
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SpartanIvy posted:It's hard to shop a Trane. Nicely done. 
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Aug 3, 2022 22:59
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SpartanIvy posted:It's hard to shop a Trane. I don't post much in this thread, but I know a new thread title when I see one
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Aug 3, 2022 23:21
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His Divine Shadow posted:I noticed last winter that my heat recovery ventilation system was only 60% efficient but it should be more like 80%+. I finally took a look at the attic and yeah, I guess the answer is pretty plain, insufficient insulation around the ducts. I am buying more insulation and wrapping around the ducts soon. I've been wondering if I should dig away and wrap the insulation all around the ducts, or if I should like get bigger mats and lay them over the ducts so that they and the area around is covered like a blanket. If it were me I'd just reinsulate the entire attic. It looks like you've got a good amount of space to work with, so just add another foot or so of blown-in to cover up the pipes (and the entire attic floor while you're at it). You could wrap the pipes more but that's going to be pretty minimal.
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Aug 4, 2022 00:47
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I've been looking into an ERV install since my house has abnormally high CO2 concentrations. It seems like it's still deeply niche, I only found one contractor in my area who even responded, and they quoted $4500 for my 2000 ft^2 home. I'm pissed off enough to look into just buying one, which is about $1k for 300cfm, and it seems to be generally an easy install where I need two 6" cuts on my return duct in the basement, plus two 6" cuts in my vinyl-over-wood-1993 exterior and a handful of insulated duct. This would be the first time I do anything HVAC aside from a thermostat. For those who know better- is this in the realm of a DIYer, and are there any good tutorials out there for doing this sort of ducting? I'm wading through the sea of bullshit in youtube and debating calling a professional to handle the ducts.
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Aug 4, 2022 13:32
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Finally got the quote from Trane. To recap -- the house is 2800 sqft, with a big (~1800 sqft) first level, with 17' vaulted ceilings that give the house a ton of volume. Second story has 3 large bedrooms and lovely airflow. It's in Central Ohio. The existing AC unit is 3 ton. Lennox and Goodman quoted 4 ton units. Trane said they did a load calculation and didn't want to go past 3 ton because anything larger would cycle too much for proper dehumidification, even with multi-stage. I don't understand that logic. The 2 stage unit I'm looking at with Goodman runs at 65% and 100% capacity. 65% of 4 ton is 2.6 ton... seems like that should provide additional capacity and the ability to throttle down, am I missing something? meatpimp fucked around with this message at 17:31 on Aug 4, 2022 |
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Aug 4, 2022 17:06
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DkHelmet posted:I've been looking into an ERV install since my house has abnormally high CO2 concentrations. It seems like it's still deeply niche, I only found one contractor in my area who even responded, and they quoted $4500 for my 2000 ft^2 home. I'm pissed off enough to look into just buying one, which is about $1k for 300cfm, and it seems to be generally an easy install where I need two 6" cuts on my return duct in the basement, plus two 6" cuts in my vinyl-over-wood-1993 exterior and a handful of insulated duct. When I looked at this, the hardest part seemed like balancing the airflow. It seemed like you'd need a manometer, which is fairly inexpensive if you've got a quote for $4500! I ended up putting in a whole house dehumidifer with an outside air inlet as part of it. The inlet only runs when the CO2 sensor indicates it needs fresh air. We were having humidity issues inside as well, so this made more sense then an ERV. Ductwork is not hard, so I'd expect this to be well within DIY territory.
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Aug 4, 2022 23:15
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I don't know if I'd call duct work easy. I suppose flex duct is easy, but with rigid back when I was helping out with residential installs a couple decades ago, we never regretted paying a few hundred to have a sheet-metal guy do that stuff for us. There's an art to doing it fast and neat.
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Aug 5, 2022 15:30
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glynnenstein posted:I don't know if I'd call duct work easy. I suppose flex duct is easy, but with rigid back when I was helping out with residential installs a couple decades ago, we never regretted paying a few hundred to have a sheet-metal guy do that stuff for us. There's an art to doing it fast and neat. Not to mention that ducts are often in very inconvenient locations. But arguably there's an art to doing anything fast and neat, and for a DIYer air ducts are easy to comprehend in how they function and pretty safe if you mess up - not like plumbing with potential for major water damage or electrical things with fires or electrocution as worst case scenarios.
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Aug 5, 2022 16:44
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Having done it, it's easy if you have attention to detail and don't mind buying about half a grand in tools for it, and also don't mind losing some blood and getting some stitches before you catch on to the fact that sheet metal is sharp and you can't work tired around it. My only regret is installing my system on my kitchen ceiling in an enclosure instead of running another 8 feet of 2 ducts and seriously improving serviceability.
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Aug 5, 2022 22:06
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nwin posted:I wasn’t home today but my wife turned the bottom unit off and the upstairs worked way better. HVAC company has been called. Any luck on this? When does your contractor come out? I'm really curious as the to the answer.
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Aug 5, 2022 23:34
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H110Hawk posted:Any luck on this? When does your contractor come out? I'm really curious as the to the answer. Ha. They “misheard me” and thought I had rescheduled yesterdays appointment. So they couldn’t come out yesterday. They’re scheduled for Monday morning. We’ve had some luck raising the temp on the downstairs unit but that’s it. As soon as the sun sets both of the units work pretty well in tandem.
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Aug 5, 2022 23:36
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What profession sizes and designs sfh HVAC installations? Is this a lookup table kind of thing or a really mathy kind of thing or what? That is, where do these residential systems come from?
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Aug 6, 2022 00:37
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slurm posted:What profession sizes and designs sfh HVAC installations? Is this a lookup table kind of thing or a really mathy kind of thing or what? That is, where do these residential systems come from? An engineer or competent contractor can use a combination of the ASHRAE fundamentals manual and the ACCA manual J calcuation to properly size a residential HVAC system. Then they'll install a properly sized system (half the battle) using good installation practices (the harder half of the battle). These things cost time and money so usually people won't pay the guys who will take the time and have the capability to do these things. Most contractors will put in what was there before. Some will put in whatever size they have available. Others will use rules of thumb that are often outdated. Usually this works "good enough". Edit: I forgot the obvious. Cost. These things are all super cost driven, which is why forced hot air is the most common heating method. It sucks, but you get to double up and use the ducting for AC so it's the lowest total system cost. Logic like this, repeated over and over, which leads to "good enough" again. It's all good enough to get a stamp on it, but often it sucks to live with. TacoHavoc fucked around with this message at 01:22 on Aug 6, 2022 |
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Aug 6, 2022 01:18
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Mechanical engineers who didn't have good enough grades to work for defense contractors. people typically use a simplified method called "Manual J" to size residential units. you don't have to be a full on enginerd to use it though. there are software packages that do the crunchy bits for you.
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Aug 6, 2022 01:19
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Anyone have a breakdown on the HVAC tax credits in the IRA bill that just passed? Most articles I’ve seen are pretty high level. I’m trying to figure out what qualifies and what the maximum tax credit is—I’ve seen some articles that say it’s a 2000$ credit, but the old program maxed at $300 I think?
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Aug 8, 2022 03:43
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devicenull posted:If it were me I'd just reinsulate the entire attic. It looks like you've got a good amount of space to work with, so just add another foot or so of blown-in to cover up the pipes (and the entire attic floor while you're at it). You could wrap the pipes more but that's going to be pretty minimal. You know, I didn't write about this because I was feeling pretty stressed out about it. After I went in and looked closer at the blown in insulation I found it was only 100mm or even that. I was flabbergasted, this house had less roof insulation than a british home (I read 200mm there) and it's been like this since 2014. This must be a mistake I thought, I went and looked at my house blueprints (I got the prints for everything, structure, water, ventilation, electrical etc) and double checked and yeah, I'm supposed to have 500mm of blown in insulation, not less than 100mm! Holy poo poo I've been living since 2014 with almost no insulation, I can't believe we haven't noticed it. The ducts are supposed to be buried in this stuff and not exposed at all. We have an annual consumption of 11,000 kWh, but that also includes direct electric heating in my shop so I figured that takes 2-3000 kWh on its own and 7-8000 kWh for the house and I thought that sounded OK since our house is electrically heated too, with a heat pump. I am kinda amazed how well it has worked despite all that. At any rate I contacted the company who built my house and showed them the photos and told them what I discovered, that was friday. They phoned me just now and apologized a lot and they will be sending a truck as soon as possible, inside two weeks and putting 500mm of blown in insulation in my attic. EDIT: went in and checked our electricity consumption for the last 12 months, 9850 kWh (!), impressive IMO. We did try and save power this year, lowered the indoor temps and used our accumulating masonry heater to get the temps up. It's gonna be interesting to see next year how much this lowers our consumption. I have a feeling we're gonna save a lot of money. I also have a feeling the building company knows that and are happy we're not trying to get them to pay for that.... His Divine Shadow fucked around with this message at 09:04 on Aug 8, 2022 |
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Aug 8, 2022 08:40
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Wow thats nuts. An extra 400mm of insulation should dramatically reduce your need for hvac use. You might want to rent a FLIR camera to the rest of your house and make sure nothing else was overlooked.
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Aug 8, 2022 15:37
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My HVAC usage is soley for ventilation and is itself an energy conserver most of the year since it recovers the heat from indoor air. The house is so tight that without it running bad things happen, the first year we ran it on the lowest setting and got condensation issues indoors, need to be run at 2nd or higher setting. The funny thing is they did a FLIR scan when the house was new. I dunno how they missed that. But I think they mainly looked at the doors and windows.
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Aug 8, 2022 15:47
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His Divine Shadow posted:My HVAC usage is soley for ventilation and is itself an energy conserver most of the year since it recovers the heat from indoor air. The house is so tight that without it running bad things happen, the first year we ran it on the lowest setting and got condensation issues indoors, need to be run at 2nd or higher setting. Fair enough! In that case it's probably fine to skip. The FLIR scan would have shown a nice blanket of the same color on the ceiling so wouldn't have raised any red flags.
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Aug 8, 2022 15:53
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H110Hawk posted:Any luck on this? When does your contractor come out? I'm really curious as the to the answer. So this is second hand from my wife but apparently on the condenser they can change how much refrigerant each unit receives via some dip switches. They’re changing it so the upper level receives more and are running a final test on the system. I asked about possible leaks or needing to recharge the system and they said they looked into that but everything checked out fine. I guess we’ll see how it works over the next few days. Edit: wife is saying it’s already way better upstairs and downstairs is remaining cool, so that’s good. The company also said that the condenser was more than big enough to handle both units and I could throw in a third split without issue if I ever finish the basement and go that route, so the capacity is definitely there. nwin fucked around with this message at 23:21 on Aug 8, 2022 |
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Aug 8, 2022 16:35
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His Divine Shadow posted:You know, I didn't write about this because I was feeling pretty stressed out about it. After I went in and looked closer at the blown in insulation I found it was only 100mm or even that. I was flabbergasted, this house had less roof insulation than a british home (I read 200mm there) and it's been like this since 2014. Good for you! And good that the builder is coming back after 8 years to fix this!
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Aug 9, 2022 01:16
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