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devicenull posted:Thanks! We're currently getting quotes for air sealing + blown in insulation in the attic. We have what's original to the house (from the 60s), where it's present at all... a bunch of it got removed due to water damage or terrible decay. I'm still waiting on the results of the energy audit.  a bunch of blown-in insulation into your attic, run far and run fast. A 60s-70s-era home's shell is going to be absolutely porous with 1" to 4" holes drilled all over in the studs, etc. There's actually a new construction spec these days, which is the dude who just walks around after all the wiring and plumbing got drilled and pulled threough a building frame - and he just shoots every hole with sealing foam. Probably a pretty chill job!You're throwing around some terminology I'm not yet familiar with such as the R22 (which appears to be an outdated model of AC unit which shits ozone everywhere or something), and unless you've been doing a lot of personal homework I'd be curious where you heard that name-dropped, because I've taken a couple dozen credits and never heard that come up (yet, hands-on HVAC maintenance is next term)... Mainly because I'm leery of salespeople taking advantage of consumers by boggling them with stuff neither of them understand - not that I'm accusing you of being ignorant but I've already run into a few people being led down a road to an unnecessary upgrade for their situation. Where do you live, state, county, elevation? Hearing about your temps in the last month isn't a ton that's helpful to work off of however, it sounds as though you either avoided the extreme cold front waves that've been shocking a lot of areas in N America (if you aren't being flooded or blown to Oz, of course), and without knowing where you live or at least what kind of climate you exist in year-round, I wouldn't feel comfortable sharing my limited knowledge in a vacuum and it then being applied to somewhere it wasn't super-appropriate for. I live in the PNW and am much more familiar with heating-based climate rigors, but as long as I can look it up on the epa.org website (if Trump hasn't nuked it yet) I can probably find out what your average daily temps were for the last few decades.  I will try not to name-drop any stuff which is not free and/or publically accessible, btw. the EPA's Portfolio Manager is free to everyone, and it's really easy to mess around with. If you own multiple properties, it's worth spending an hour or two poking around in it. edit: for those who haven't looked it up already, a "blower door test" is where they literally stick a bigass fan the size of a door and then vent it out of your home and then gauge the pressure sifferential coming from inside, with what the fan COULD be blowing at if it wasn't bottlenecked... If you didn't have a crew come out to your house for an hour or three and gently caress with a ~3'x7' in an extrenal entry door, then it didn't get done. coyo7e fucked around with this message at 02:30 on Jan 25, 2017 |
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Jan 25, 2017 02:10
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coyo7e posted:If nobody ever mentions the words "blower door test" and they're claiming to be coming in to seal your home by Hah, I'm surprised you have't heard about R22 yet. It's a old refrigerant that's not produced anymore (because it's terrible for the ozone layer). Prices have shot up dramatically these days, and it's apparently getting harder to find. Go back a page or two here, and you can find pics of my ancient AC. We had one place come out and do a blower door test.. I think the number they gave me was around 750cfm (but I haven't received the final report, so I'm not completely sure). They were talking about air sealing *before* doing the blown in. I've already done a bunch of that (I've gone through 5 of the 24oz spray foam cans already), and I'm confident that's part of what they're going to do. I'm in the middle of NJ, and the state currently has some incentives - http://www.njcleanenergy.com/hp . My house is 1400sqft, on a slab.
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Jan 25, 2017 02:31
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devicenull posted:Thanks! We're currently getting quotes for air sealing + blown in insulation in the attic. We have what's original to the house (from the 60s), where it's present at all... a bunch of it got removed due to water damage or terrible decay. I'm still waiting on the results of the energy audit. Even if it's cheaper to run, you are used to the high vent temps of gas heat, and your comfort level is going to noticeably drop at best. At worst, the heat pump rarely keeps up and you're burning 10kW+ heat strips all of the time. -NG is probably going to be relatively stable in price. Electricity is a changing market, and utilities are moving to demand rate structures which may or may not work out in favor of a heat pump, either. -The federal credits for solar have/are drying up. Utilities have little reason to incentivize it on their own. This is a discussion on its own, but the economics of solar are only edge-case favorable now and unlikely to improve in the near future. I wouldn't bank on a heat pump on the assumption it'll pay off even more with 'free' energy later.
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Jan 25, 2017 02:43
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angryrobots posted:-The federal credits for solar have/are drying up. Utilities have little reason to incentivize it on their own. This is a discussion on its own, but the economics of solar are only edge-case favorable now and unlikely to improve in the near future. I wouldn't bank on a heat pump on the assumption it'll pay off even more with 'free' energy later. When you flat-out claimed that utilities have no reason to incentivize, you would seem to be working from a position of a vacuum of knowledge around it. But that's not as much for the HVAC thread as the Energy Production thread in AT, which seems mainly to have been overrun by pro-nuke goons with no electrical or electronics know-how. Solar, well, its cost has bee dropping shockingly lately, and if you're a goon I'm kind of surprised you don't have a foldable solar charging station with multiple USB-outs or something, if you haven't just cobbled together your own from old LED solar lawn lights on close-out. coyo7e fucked around with this message at 03:16 on Jan 25, 2017 |
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Jan 25, 2017 03:14
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R22, chlorodifluromethane, has been the most common residential refrigerant for the last 30 years or so. It's an HCFC with less ozone depletion potential than dichlorodifluromethane, R12 and a CFC, but has pretty massive global warming potential. It's been phased out on a timeline established by the Montreal protocol in the early 90s.
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Jan 25, 2017 03:14
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glynnenstein posted:R22, chlorodifluromethane, has been the most common residential refrigerant for the last 30 years or so. It's an HCFC with less ozone depletion potential than dichlorodifluromethane, R12 and a CFC, but has pretty massive global warming potential. It's been phased out on a timeline established by the Montreal protocol in the early 90s.  I've mainly been oriented around construction theory in terms of sustainability and energy efficiency, retrofitting existing structures, and drafting.
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Jan 25, 2017 03:18
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So I finally broke down and had a local shop with a good reputation come in and fix my return and supply ductwork. They also replaced my old 2 ton goodman A/C with a 3 ton carrier heat pump that matches the newer carrier propane furnace I had installed 2 years ago. I may have them come back and drill another hole through the house for the furnace air supply, but to my knowledge it's never been hooked up that way. Before:  After:  Feels so good not having to worry about propane cost so much any more. I had the tank filled yesterday, 400 gallons at $1.47 a gallon, should last the whole year. My next purchase will probably be my own 1000 gallon tank. To add to the discussion, I live nearest to Evansville, Indiana. My REC currently charges $0.10516 per kWh. The heat pump has a COP of 2.64 @17F and 3.92 @47F. It's cheaper 100% of the time to run the heat pump the way things cost right now, although it won't keep up with the demand much below freezing.
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Jan 25, 2017 03:18
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coyo7e posted:Yeah, I think I haven't come across it because as I said I'm not literally working inside HVAc units yet and am more working on how to perform audits for residential and commercial structures with some lighting stuff thrown in . I am kind of pissed off about that actually because I didn't realize that, if I'd taken one extra electrical engineering class, I could have skipped over 12 months of not actually doing anything for an internship except crawling around in attics and crawlspaces. Wait, I thought you were just being facetious, did you really not know what R22 was?  rdb posted:So I finally broke down and had a local shop with a good reputation come in and fix my return and supply ductwork. They also replaced my old 2 ton goodman A/C with a 3 ton carrier heat pump that matches the newer carrier propane furnace I had installed 2 years ago. I may have them come back and drill another hole through the house for the furnace air supply, but to my knowledge it's never been hooked up that way. That looks so much better! I can believe anyone signed off on what the old unit looked like.
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Jan 25, 2017 03:29
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coyo7e posted:I would like to object, here. Do you have experience in Commercial HVAC (I'm not saying did you "instal AC professionally at any point" - but rather asking if you "worked on large commercial/industrial structures with non-residential usage patterns, or at least have studied it, fluid dynamics, etc"), or utilities and how they operate (pricing-wise, demand-wise, peaks, assumed loads, whatnot), and do you have any experience installing and utilizing solar, using inverters to push power back to the grid, etc? No, I'm in the utility power business, and my comments on solar were in direct reply to the poster intending to generate at the hobbyist/residential level as a reason to go from gas heat to electric. They were not intended as a sweeping rebuke of solar in all situations, and that's a derail I'm not trying to start. I am pretty familiar with how utilities operate, and their (non PR) opinion on solar. I think maybe that should be a thread of its own, cause I know exactly what you mean about that a/t thread.
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Jan 25, 2017 03:48
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Are variable capacity heat pumps a thing for residential forced air systems? It would seem nice to be able to pump a lot of heat on cold days without aux heat but not be oversized for the summer.
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Jan 25, 2017 04:26
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Alereon posted:Are variable capacity heat pumps a thing for residential forced air systems? It would seem nice to be able to pump a lot of heat on cold days without aux heat but not be oversized for the summer. yes. I've got a carrier greenspeed, but all the major brands have a heatpump version in addition to straight cool. It's fabulous.
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Jan 25, 2017 04:32
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coyo7e posted:What "boxes" is this thing ticking? You mentioned that "15 degree differential AC is a fact of life", so I'm assuming you're looking at an outside average air temp of, say, 80F? (Most heating degree day calculations use 65F as baseline for indoor temp, if you go higher or lower please mention it, say if you're elderly, or have a newborn baby, or if you are a polar bear like my old roommate who left everything at 50F and wore lots of sweaters.) How big is your building (can't do gently caress-all without sq footage really)? How many stories? What's it's orientation? If this a home, or a business? Temperature Differential is unrelated to outside air temperature. The actual calculation is TD = coil temp - return air temp. That means that the air coming off the coil (and out of the vent) should be within about a degree of the rated TD on the evaporator/condenser. More or less indicates a problem with the system. TD isn't fixed either, I usually run R-707 freezer systems with a TD of 12-20 degrees, with 20 degree TD's primarily on systems that require fast freezing or holding ice cream.
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Jan 25, 2017 07:28
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devicenull posted:Do heat pumps ever really make sense when natural gas is available? I've been playing around with heatcalc.xls, and it seems that it's always more expensive to heat with a heat pump. It really depends on the cost of electricity. For reference, I pay $0.105/kWh, so its a lot cheaper for me in TX to use a heat pump. The other issue is how cold do your cold days get? Heat pumps become wildly inefficient when the outdoor temp drops below about 17 degrees F, because there just isn't enough heat in the outside air to move inside.
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Jan 25, 2017 07:34
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devicenull posted:We know our AC is from 1989 and uses R22, so replacement in the near future seems pretty likely. I'd prefer to do it on my terms (rather then waiting for failure), especially when I can get a $10k interest free loan from the state for it. So you have existing ductwork and want to........tear it out? That doesn't make a lot of sense. HVLP systems are pretty much designed for retrofits into places where normal ducting would be too large/obtrusive. See the other post about ceiling fans. And the other one about how noisy HVLP systems can be. Having an old R22 unit is not a reason to do anything more than replace the inside/outside units and have someone go through your ductwork to make sure it's properly sealed still (hint: it's not if it's that old).
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Jan 25, 2017 22:40
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Motronic posted:So you have existing ductwork and want to........tear it out? That doesn't make a lot of sense. HVLP systems are pretty much designed for retrofits into places where normal ducting would be too large/obtrusive. See the other post about ceiling fans. And the other one about how noisy HVLP systems can be. Nah, you confused me with someone else. We were actually considering new ductwork (all ours is buried in the slab... fun), but not really seriously.
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Jan 26, 2017 00:09
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coyo7e posted:Yeah, this is my concern as well. I'm going to guess that he wants to set the thermostat at 75°F on 90°F days, or 80°F on 95°F days, because Miami.
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Jan 26, 2017 03:30
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devicenull posted:Nah, you confused me with someone else. We were actually considering new ductwork (all ours is buried in the slab... fun), but not really seriously. Ahhh, that makes much more sense then. Yes, for a poo poo show ductwork runs HVLP is probably a trade-off that is worth making. Just make drat sure you have the right installers, because the noise can be largely mitigated by a properly balanced install. Most setups that are super noisy don't have sufficient return capacity in enough places.
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Jan 26, 2017 16:20
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So it turns out my Nest thermostat sucks balls with a dual fuel heat pump. I really need an ecobee3. The only thing a nest will do is switch between the two based on a outdoor lockout temp. It doesn't take into account how long temperature takes to rise or how far below the set point it is. Which is kinda funny because when I had it hooked up to the gas furnace and outdoor wood boiler it would, so the functionality is there just not enabled for all setups.
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Jan 26, 2017 23:12
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Motronic posted:Ahhh, that makes much more sense then. Yes, for a poo poo show ductwork runs HVLP is probably a trade-off that is worth making. Just make drat sure you have the right installers, because the noise can be largely mitigated by a properly balanced install. Most setups that are super noisy don't have sufficient return capacity in enough places. If we ever get the ducts moved, it seems pretty straightforward (assuming we run it all in the attic, and do ceiling registers). Only one floor, attic is pretty easily accessed. One major upgrade at a time though...
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Jan 28, 2017 01:13
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devicenull posted:If we ever get the ducts moved, it seems pretty straightforward (assuming we run it all in the attic, and do ceiling registers). Only one floor, attic is pretty easily accessed. One major upgrade at a time though... If you have an attic and a single story home that is not "poo poo show duct runs". I'm talking about 2 story 1700s farm houses with 2 foot thick rock/rubble walls and multiple 1800s/early 1900s additions. You need to find good contractors in your area and ask them for quotes and recommendations before you decide you need a particular type of system.
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Jan 28, 2017 02:11
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Alereon posted:Are variable capacity heat pumps a thing for residential forced air systems? It would seem nice to be able to pump a lot of heat on cold days without aux heat but not be oversized for the summer. Someone correct me if I'm wrong, but heat pumps and reverse cycle a/c are the same thing, right? And that should mean a variable capacity heat pump is the same as inverter reverse cycle a/c. If so, we just had a 14kW reverse cycle ducted Panasonic inverter system installed a couple months ago, and it's awesome. Will do from 3.3 - 15.5kW of cooling, and 4.1 - 18kw of heating, max actual power draw of around 5.5kW or so. Has no problem keeping our poorly insulated 1980s house cool here in Perth even in temps above 40C, and the power draw when it's idling at night is only around 600W or so. I could see the temp range of -20C to 46C being a problem in places like the midwestern US, but it's perfect here where temps never drop below 0C. It's great combined with the 5kW of solar I had installed at the same time, on all but the hottest days the power draw of the A/C is lower than the generation of my solar panels (thanks to the inverter that doesn't need to cycle on and off), so it often costs me nothing to run. Compared to what my power costs would be without solar, the panels will pay for themselves in about 3-4 years. Here's a good example of the power draw I see with my reverse cycle inverter:  You can see where I turn it on just after 9AM (black line), and then it ramps up and down throughout the day, peaking in the late afternoon at the hottest temp, then ramping down during the evening as the house cools. Most of the day it stays under my solar production (green section)
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Jan 31, 2017 07:40
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a 3 or 4 year roi is incredible for a residence, your utility provider and neighbors should thank you.
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Feb 1, 2017 00:34
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Any recommendations for a low-end IR temperature gun? I am not looking for an IR camera with PnP or anything like you'd use for a blower-door test and walkthrough to show to a client - just your basic one I can point at stuff to get a reasonable temperature reading. If it's small and cheap, even better.. I'll probably have to invest in a better one eventually but for now it's more important that it fits in my tightly-packed little bag of tricks and is cheap.
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Feb 11, 2017 21:59
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https://www.amazon.com/dp/B006V4WNYU/ref=cm_sw_r_cp_api_ZW3Nyb090FX5G Doubles as a cat toy. 
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Feb 11, 2017 22:04
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MrYenko posted:https://www.amazon.com/dp/B006V4WNYU/ref=cm_sw_r_cp_api_ZW3Nyb090FX5G Can confirm, use way more often as cat toy than as legit test equipment.
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Feb 12, 2017 18:00
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So, dumb question... My house has two returns, a big one near the furnace, and a small one way off in the back of the house. The big one has a filter on it, but the small one doesn't. I had my head shoved up in the big one, and noticed the flex duct going to the small one is caked in dust. Should I have some type of filter on the small return? Back when we bought the house, the home inspector said it was normal to not have a filter there... but we've since found out he was a complete idiot. The small return is only 12x6ish, and I think it has 5 inch flex duct.
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Feb 18, 2017 02:08
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Do you have a filter on the furnace itself? The answer is always filter return air. If possible I would just replace the flex, rather than try to clean it, and put a filter-grill on the return.
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Feb 18, 2017 02:25
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MRC48B posted:Do you have a filter on the furnace itself? No, there's a filter on the main return grille and that's it. Replacing the flex might be feasible, but tricky. The return is in the attic, but there's not really enough head room to make it to where the return is. It might actually be easier to replace it with metal... I could make up a big ~15 ft section, and just push it through the attic. Attaching to where the existing return is might be a little tricky. lovely mspaint: 
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Feb 18, 2017 02:40
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If you're gonna go through the trouble of removing duct and/or return grilles, you'd probably have a much easier time just installing a filter rack at the unit. Especially if the smaller grille isn't already a filterback grille. If it isn't then you're gonna need to remove it and cut the drywall and box to fit a larger grille.
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Feb 19, 2017 02:42
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We have ducted reverse cycle A/C and I was recently in the roof, and the ducts look badly positioned and not very straight. Should the ducts be the shortest path with minimal bends or is there some weird air/fluid dymanics thing where there should be a bunch of bends? I'll try and get a photo of what I mean but it's currently summer and hot as gently caress up there.
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Feb 19, 2017 04:09
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Spookydonut posted:We have ducted reverse cycle A/C and I was recently in the roof, and the ducts look badly positioned and not very straight. Should the ducts be the shortest path with minimal bends or is there some weird air/fluid dymanics thing where there should be a bunch of bends? Reverse Cycle = Heat pump right? Ideally, yes, you want your ducts to be straight and avoid bends when possible. More bends = More turbulence and poorer air delivery. In reality, most installers don't give a poo poo and install terrible spaghetti monsters.
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Feb 19, 2017 04:17
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ExplodingSims posted:Reverse Cycle = Heat pump right? Yes apparently reverse cycle means a heat pump. How hard would it be to rearrange it to straighten out the ducts? http://imgur.com/a/hBmAA
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Feb 19, 2017 05:19
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If you're loving with venting up in the attic, you could very well be depressurizing the home's shell and either pulling in gases from below the crawlspace, or accidentally forcing furnaces and other stuff with gas-fed pilots, or fireplaces etc, to blow out or in-vent. I hope you know a lot about pascals
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Feb 19, 2017 05:22
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Spookydonut posted:Yes apparently reverse cycle means a heat pump. It's not impossible, but it would be a fair amount of work. By the time you're talking about cutting, rearranging, and reconnecting all the ducts, you'd probably have a much easier time just getting new ductwork. Especially since it all seems to be ductboard and flex, which is cheap and easy to work with. But judging by that picture, it looks like it's a mess already. The best setup for something like that is to have one solid ductboard trunk, that the flex comes off of to individual drops. The flex should be pulled taught and supported from the rafters, ideally staying straight as possible. Also trying to avoid those box plenum things. And from what I can tell, your setup has none of that going on.
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Feb 19, 2017 05:39
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coyo7e posted:If you're loving with venting up in the attic, you could very well be depressurizing the home's shell and either pulling in gases from below the crawlspace, or accidentally forcing furnaces and other stuff with gas-fed pilots, or fireplaces etc, to blow out or in-vent. It's a single story house with no gas or furnances (Australia). ExplodingSims posted:It's not impossible, but it would be a fair amount of work. By the time you're talking about cutting, rearranging, and reconnecting all the ducts, you'd probably have a much easier time just getting new ductwork. This is what I was afraid of. The guys who installed it were apparently really poo poo.
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Feb 19, 2017 05:55
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HVAC techs are almost always some redneck who thinks "engineers make his life harder.". I mean literally if they don't even CLAIM to be an engineer - you're going to get some hillbilly who's using a basic floor-space/volume calculator, where he'll sell you a unit because that's what they have on the piece of paper. He won't even understand that differing humidities can require differing HVAC loads - and be insulted for being asked some stupid question like that. In AUS you've got a pretty-low relative humidtiy, I think? If your HVAC guy doesn't even know what "enthalpy" means then you should chase him off of your property because he's a glorified ar salesguy who probably barely-graduated K-12 schooling and is now going to cost you THOUSANDS of dollars on his expertise - and you won't ever get away with suing them etc, lmao
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Feb 19, 2017 08:17
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Australia is a little bit more hardcore on the licensing for AC installers and technicians- need to be licensed through the government and you cant get licensed unless you've undertaken tertiary studies in the field of AC you want to work in- So if your doing automotive you need to have a qualification in basic mechanics as well as one in AC systems. Home installers need to have a trade certification in home AC installs and be a licenced electrician if they're hooking the units up too. Industry (at least where I am) is fairly well regulated too- You'll still get some cowboys out there but they end up either getting smacked by the government regulators or get such a bad reputation that word of mouth becomes poison for them. You also wont find solid ducting outside of commercial installs in Australia too- its all that insulated flexible tubing. We've got more issues with roof spaces hitting 60 degrees and needing to keep the air in the ducts cold than it being -10 inside your roof and having issues with frost and heat loss causing your home to freeze. Sealed homes just arent a thing here, mostly because they would become an absolute oven after a week of 40+ degree days and 30 degree nights.
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Feb 19, 2017 11:12
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This only makes me less impressed with my own schooling - "they don't have time for" cooling-based environments or using celsius and joules instead of Btus and Fahrens. Hopefully I can learn enough to gtfo and be the red-headed stepchild in some other nation
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Feb 19, 2017 11:36
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coyo7e posted:HVAC techs are almost always some redneck who thinks "engineers make his life harder.".
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Feb 19, 2017 13:48
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angryrobots posted:From what you've posted, everything you know is theoretical. You have little knowledge of accepted practice, installation methods or materials. Your "advice" is obtuse and unhelpful. Frankly if I had to choose between the hillbilly and you, I'd take advice from the hillbilly. At least the hillbilly would know what R22 is. That's like going to an engine mechanic and having to tell him that your cars engine needs oil to run. If I had a nickel for every grocery store I service that is totally jacked up in some way because of bonehead engineering I'd be a very rich man.
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Feb 26, 2017 15:13
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