Ask MetaFilter questions tagged with HVAC

Vedi, Vici, Vent-y?

Nice Guy Mike — Fri, 04 Dec 2009 21:23:03 -0800

Furniture partially blocking a HVAC return - bad idea or really bad idea? After a recent move to a new place, I find myself looking at the slightly-sub-optimal furniture layout in the living room and looking for alternatives. Ideally I'd like to switch some items around, but my currently-favoured layout would place a tall bookcase completely obscuring a HVAC return.

I don't have much experience with forced-air HVAC systems, so I have no idea how bad an idea this would be. Any inputs?

Additional information: The return is one of two in the property (it's a 12"x12" compared to the 24"x24" one upstairs), the property is a townhouse with a double-height area over the living room, so it's technically a contiguous space that's serviced by both returns - that said, the upstairs return is at the front of the house and the downstairs is at the back).

The bookcase would be one of several in a row, and all would stand off from the wall by 1-2", so we're not talking about sealing the area off. I am aware that changing the filter would be very difficult, but am I risking damage to the system or problems with heating or air conditioning by doing so?

How to tell when a furnace is on its last leg?

Nonce — Tue, 20 Oct 2009 10:19:16 -0800

I have a 20-year-old furnace. The HVAC person is coming today to do a minor repair (expected cost less than $400). When s/he sees how old it is, I fully expect him/her to push me to have a new furnace installed.

Should I? I know it's lived past its planned lifespan, but there aren't any moving parts. If nothing else is wrong with the furnace, should I insist on just the minor repair? If there are a few other minor items that need adjustment, what is the cutoff at which I should say fuck it, install a new furnace? $1,000? Or more or less than that?

It's a SnyderGeneral model GUG117A016N manufactured in 1989.

Installing Radiant Heat Flooring

crush-onastick — Mon, 19 Oct 2009 11:10:18 -0800

Chicago home improvement filter: We'd like to get an estimate for installing radiant-heat flooring in our condo (6-flat built at the turn of the last century. We own a duplex down, with the primary living area being on the ground floor) or possibly replacing the HVAC with baseboard heating. Anything, really, because the conversion from whatever-it-was to the gas furnace HVAC it now is was badly done and the place is freezing all the time. Any business or contractors you recommend? Suggestions for going about this the right way? Dire warnings? Our condo is two bedrooms, three baths, living room with a separate dining room and an enclosed sunroom. There is a small finished basement. The living room and dining room are hardwood floors; the rest of the house is carpet (except the baths and kitchen, which are tile). At a minimum, I'd like to put radiant-heat flooring in the kitchen and baths, but I'd like to find out if it's possible and financially-viable for us to convert the whole place to radiant-heat flooring or baseboard heat because the furnace doesn't do it. We've had the furnace inspected, cleaned, tuned, but it's not efficient. When it was installed, the duct-work was poorly placed (for one thing, the vents are at the *top* of extra-tall walls, so all the heat floats up to the high ceilings).

No, we have no interest in doing this ourselves. None. Not even touching up the paint afterwards. But I don't know where to begin finding someone to assess the possibility and doing the job for us. I have asked a friend--who is an architect--but he was not much help.

Installing geo thermal in an old house with boiler?

idyllhands — Mon, 28 Sep 2009 20:07:09 -0800

Installing geo thermal in an old house with boiler? I am considering buying an old (1910s) house with a boiler and radiators installed. I was thinking it would be great to convert it to run off of geothermal. How difficult/expensive would this be? I live in Kansas, so we need good heating as well as cooling for summer. I was hoping to accomplish both with a geothermal system.

Wonky Air Conditioner: Any HVAC People Out There?

extraheavymarcellus — Sun, 13 Sep 2009 15:27:56 -0800

I was wondering if anyone has any experience with LG Multi-zone air conditioners? We have a multi-zone system that has been working fine until recently. Now, when I try to run the AC I get a flashing CH 26 and CH 46 error on the units. They work fine if we just use the fan settings. Do I have a bad compressor/inverter or is it something worse?

Can I get Fed Tax Cred for Energy Efficiency on a home purchase?

dpollitt — Tue, 01 Sep 2009 14:18:45 -0800

Can I get the Federal Tax Credits for Energy Efficiency if I am buying the house right now, and the current homeowner is replacing the furnace for me? I am in the process of buying a home, and during the inspection we found that the furnace needs to be replaced. The homeowner has agreed to put in a basic one, but has given us the option to 'upgrade' to a more efficient model at our cost.

The question is, if we are paying for part of the furnace, who would qualify(if they met all other conditions) for the tax credit? The credit could be as much as $700, and the extra cost of a more efficient furnace is around $900, so I think it makes sense to try to get it if we can.

If the seller is the one who qualifies, is it a bad idea to try and convince them to pay the extra and claim the tax credit? Maybe even if we include the difference?

HVAC Filter MERV ratings - which is best (for my usage)?

torquemaniac — Fri, 12 Jun 2009 12:09:39 -0800

HVACFilterfilter: It's time to get a new filter for my residential HVAC system. Please help me understand MERV ratings. I've done quite a bit of research and it appears to me that MERV rated filters up to about 6 or so are used mostly to keep the insides of the HVAC unit itself clean & operational and that filters rated 7-12 are used for further conditioning the air itself. I.E. - filtering out dust/dander particles to prevent them from being breathed in & keeping the house cleaner as well. Is this assumption correct? In theory I can see it, does real world experience bear this out?

My house is a small 1000sf open plan with one bedroom that stays mostly closed off & a small bathroom that mainly stays open. I live with a flock of 9 parrots, three of which are old world birds who produce a *lot* of dander. Will the higher MERV rated filters help with the dander/powder? Or should I just keep dusting regularly & get the lower MERV (and substantially cheaper) rated filter? I'll note the air return is right next to the front door and away from most all activity in the house.

The filters themselves range anywhere from $8USD x 12 (MERV 6) to $16USD x 6 (MERV 12) when bought in bulk. They're generally $15 - $50 when sourced individually. I'm concerned that not only are the higher rated filters substantially more expensive, it appears they require a more rigid rotation schedule and could possibly bind up or air lock my HVAC system. I'm using a 20x20x4 filter which should get between 3 (Merv 12) & 6 or more (Merv 6) months per filter - which makes it look like the higher rated units are at least four times as expensive. The one that came with the unit when it was new a little over a year ago was touted as "change every year or two" by my HVAC guy - I took it out and banged a lot of the powder off it before firing up the A/C for the summer today & it seems to be working fine. I don't want to push it, though. I called my HVAC subcontractor and they didn't have a clue. So, here I am, trying to figure this out before dropping a huge chunk of change on a bulk purchase of filters I'll be using for the next few years. TIA!

What's are these bits of residue that drift down out of my ceiling vent?

Askr — Thu, 21 May 2009 08:31:02 -0800

What are these brownish-blackish floaty smudgy bits that drift down out of my ceiling vent at work? Is the stuff dangerous? We moved into a new (to us) office several months ago that I believe was built in the 1970s for whatever that's worth. Over my desk is one of those square metal ventilation grates/vents that takes up half the space of one of those standard rectangular acoustic ceiling tiles. Whenever the AC comes on, little bits of brownish-blackish-grayish... stuff... occasionally but persistently float down out of it. For example each morning I have to blow a light speckling of it off my desk, and it accumulates again by the afternoon.

The stuff is light enough to float down fairly gently and to be blown away easily, but it's not fuzz consistency. The bits vary in size from dust-sized particles to chunks that are about the size of the head of a pin, but 3-D, so you only very rarely actually see one drift down, but you can easily see them collect on the pale wood of my desk. If you pick one up, it turns into a smudge easily when you smoosh it. Its composition does not appear to be uniform, but rather slightly varied.

I've looked up what asbestos looks like, and unless there is a cajun blackened variety, it's not that. We had the exterminator remove some roof rats recently, but it's hard for me to believe that they could have shit so much in the HVAC system that this neverending supply of atomized shit could continue to rain down on me for months. It happens in other offices too, which makes me think it must be the disintegrating remnants of some kind of building material used throughout the ceiling or ventilation system.

I've found this and this, which sound similar but it's hard to tell. One of them might be my same thing once it gets wet.

So WTF is this and is it dangerous for me to be exposed to this every day? Since some of the particles are so small and since the vent is right over me, I have to assume I'm inhaling some of it. Inhaling any particulate isn't ideal, but some make you sick or kill you, so, you know. Looking for anyone who has experienced and identified this more so than guesses.

What's the oily discharge coming from our central air and heat?!

GilloD — Thu, 04 Dec 2008 08:20:09 -0800

Our central AC/Heating system leaked some kind of, uh, oil (!?) last night. I have no idea what it is, the super is baffled. More inside. My wife and I have been living in our current apartment for about 6 months now. It has central air and heat, ducts upstairs and downstairs, and those ducts are covered with sheet rock or drywall- Something to obscure them and make them mesh with the walls.

We've had no problems with the AC and while the heat is INCREDIBLY HOT and dry, we've had no problems using it for the last 6 weeks or so.

Last night my wife noticed what looked like water damage spreading in a maybe 6x6 inch circle. I was concerned, so I got up on a ladder and wiped it up. To my surprise it was NOT water. It was slightly oily and had a faint odor. It reminds me of mechanical lubricant. It's a clear liquid and it had collected in a couple of fat drops within the circle, but none had dripped on the table below.

I wiped it up and aside from a very hard to see oil stain underneath the duct, there hasn't been any other leakage.

As far as I know, our heat is gas, not oil. We are on the first floor, but no one above us has had any issues.

We're flummoxed, the super is flummoxed, I was hoping MeFi might have some suggestions. As of this morning no more of the, uh, discharge had collected in that spot despite our running the heat on and off all night.

Thoughts?

It's like living inside a guitar!

bondcliff — Tue, 02 Dec 2008 07:39:40 -0800

What can I use to dampen vibrations from a water pipe? I have a heat pump in my basement, directly below my dining room. Two copper hot water pipes (one in, one out) come from the heat pump and go straight up to where they are mounted to the joists. From here they bend 90°, convert to PEX tubes, go about 10 feet across the basement ceiling where they convert back to copper and go down to the hot water heater.

When the heat pump is running these pipes mounted to the wooden joists are transferring vibrations to the hardwood floor of the dining room above. You can feel the vibrations when you’re sitting down and the noise, while not too loud, is louder than it should be. I recently attached insulation to the pipes and I think this made the problem worse.

Obviously, the pipes need to be attached securely, but I would like to mount them in a way that the vibrations are dampened somehow. Currently they are mounted with metal clips screwed into the joists. Is there something else I can mount them with, something that will isolate them from the wood?

I do not want to do any plumbing, I’m looking for solutions that don’t involve re-routing the pipes.

My HVAC shorted out!

jefficator — Wed, 26 Nov 2008 15:24:40 -0800

What did I do to my HVAC system when I changed my thermostat? Newbie "Green" American that I am, I attempted to change my thermostat to a Digital Programmable model. I neglected to turn off the power to the unit before I made this switch, and the powered "C" wire touched another wire. A tiny, almost unnoticable arc happened. The new thermostat, though wired correctly, will not even turn on the fan. I called the customer support line for the new thermostat. They directed me to touch the G and Rh wires together to see whether the fan came on. It did not. I was told this means I've blown a fuse in the heat pump itself. How do I find and replace this fuse?

The Furnace is a Janitrol A36-10. The AC is a Goodman CPKE36-1. Any thoughts? No comments from the "You idiot, HVAC is not a weekend project. You should have called an electrician" guy, please.

Looking for rectangular paintable ductwork that looks as good (and works as well) as boxing it in with drywall.

winston — Sun, 05 Oct 2008 09:12:22 -0800

We just boxed in with drywall a round 5" heating duct, running from floor to ceiling in the corner of the living room. Because of some odd features of the room, this took up more space than it should. What I'd really like is to replace the duct (and drywall) with a paintable rectangular duct running up the corner of the room, that would look just as good as drywall. This would have to be rugged enough to withstand small children playing in the room (e.g. not dent like typical metal duct). Does this exist? When I search for paintable duct, I get stuff that's intended to run across the ceiling, not be good as a wall. (e.g. I suspect that the metal duct would not only dent, but the paint would flake off when it did dent).

FWIW, the duct was already there and the renovation we just did made the box much smaller than it had been, but I want more.

The duct will have to make a 90-degree turn into a round duct immediately above the ceiling.

Energy Recovery Ventilator: good idea for cleaner air?

[insert clever name here] — Tue, 26 Aug 2008 06:13:01 -0800

I am looking at ways of improving indoor air quality, and am considering having an Energy Recovery Ventilator installed. Anyone have experience with one, if its a worth while expense. I have allergies. I have pets. I have old carpet. ( Working on removing the old carpet.) I notice in the winter, the house just seems to get stale. Sometimes in the summer to when the ac has been running for a long time (but its easier to just open a window). I have been doing some research, and it sounds like Energy Recovery Ventilator might be exactly what I should be looking for. Especially since in the winter I like to put plastic on the windows.

But, will pulling air in from the outside aggravate my allergies? Would coupling it with a whole house air purifier help? I've heard mixed reviews, including saying they really decrease the efficiency of your furnace.

I am certain that indoor air quality is an issue. I can feel it if the house is closed up for too long. And after an evening of reading about VOCs and indoor air quality, I can't imagine its NOT bad.

It's gettin' hot in herre...

odayoday — Tue, 19 Aug 2008 08:41:19 -0800

Help me keep cool! Ok, I'm a bit OCD about this I realize. I'm wondering if there's some way to test the AC in my apartment to see if it's working properly. Is there a special thermometer to use to test the air temperature coming out of the vents? If so, what should that temperature be? A little background: I live in Austin, TX. It's very hot. We've been on a tear of triple-digit days so naturally ACs will have to work harder to keep up, but even after the sun goes down it seems to take my air conditioner forever to bring the temp down just a little bit. It seems to run all night. When I wake up it is definitely cold in my place but the AC is still running. It might stop for a couple of minutes and then start up again. When it does catch up and stop it only stops for a couple of minutes before going back on. They recently had to rip up my ceilings to get any air flowing out of the vents in my kitchen/dining area b/c the ducts had been crushed or something. Now there's a tiny amount of output in the kitchen/dining area and a disproportionate amount of air output from the vent in my living room. My first bill was 120 bucks… not great but unreasonable unless you consider I spent half of the month (maybe a bit over half) at my girlfriend's apartment with the AC turned off completely. Extrapolating my utility bill rate over the course of an entire month it would have been over 200 bucks. I think over 200 bucks for a utility bill for a one bedroom apartment (under 700 sq. feet) would be absurdly high, right? My concern is that maintenance, which at this new place is notoriously slow and lazy, will just say "it's working" and do nothing even if there's not enough coolant because what do they care what my bills are? Is there any way to prove that it's not working properly? Anything I can do myself to make it run better? Should I call my own AC guy out to check it out? If the vents aren't blowing cold enough would a simple "charge" of the coolant work to fix it? They did clean the coils but I don't think that did much.

Why do split ACs make me sneeze?

phaedrus441 — Sun, 10 Aug 2008 19:08:56 -0800

Why does using the AC make me sneeze? I have a split AC (kind of like this picture), and it always make me sneeze when I use it! At first I thought it was just dusty, but I have cleaned it exhaustively and even replaced the filters, but to no avail. Also, I've noticed the same thing with other people's AC's, sometimes.

In Japan people always say don't sleep with the AC on (everybody here uses this type in their homes), and for what it's worth, I never had a problem with normal central AC back in the US.

I know there's gotta be an HVAC allergy specialist out there somewhere, so help me figure this on out! It's really hot here, so I don't think I can live without the AC, but this sneezing is slowly killing me!

Help with hot summer nights.

carsonb — Thu, 03 Jul 2008 16:17:07 -0800

Why is my bedroom consistently 10 degrees warmer than the rest of the house, and what can I do to cool it off? Here's a rough diagram of my apartment's layout. There are 4 vents for the AC, and the one intake is in the ceiling of the living room. I have vertical blinds on my south-facing window that I keep closed all day, and an oscillating fan that blows into my room from near the door. Trees block the morning sun onto my window, but noon to sundown I get direct sunlight. The vent in my room blows cold, and is not blocked at all as far as I can tell. The problem persists throughout the night. What can I do?

My outside air conditioning unit needs a Karen Silkwood shower

Unicorn on the cob — Wed, 25 Jun 2008 08:56:31 -0800

Help me de-gunk my outside air conditioner. Last year, I had a great guy replace my air conditioning unit in my five-year-old house. Being not the best homeowner in the world, I had no idea there was a vast series of weekly and monthly steps to be done to keep things nice (with the house in general), which led to me spending three grand putting in a whole new unit.

The guy told me that my outside air unit needs to be cleaned regularly to keep debris (leaves, bug bodies, crap in general) out of the blades surrounding the fan. He said the occasional high-pressure spray down with an outside garden hose would do, and that's what I've been doing. But he also mentioned that every 5 years or so, the blades in the vents would get so clogged I should do an "enzyme clean." He specifically said it was for the blades on the outside unit, NOT a duct cleaning or coil cleaning. Well, I tried calling the guy this summer and his number is disconnected, and googled "enzyme clean" and all I get is services for cleaning air ducts.

Does anyone have any experience with this? I looked at my unit yesterday and it looks pretty gunked up and I would love for it to be running as efficiently, cleanly and coolly as possible now that the 100+ degree days have started. Ideally, I would love to just do it myself, if that were possible, and he mentioned you could buy the product yourself and do it without professional help or hire an HVAC person to come and do the cleaning for you... but now I don't know who to call or what to ask for. If it helps, I'm in Dallas.

Maintenance for Dummies

ForeverDcember — Thu, 29 May 2008 20:18:07 -0800

What books can I get to not be a "dummy" when it comes to my new job? (more inside) I just took on a job as a secretary at a hospital in the engineering department. Basically, I want to know more about the technicians' jobs so I can better understand what they do and be a little more efficient in my position. I see a lot of work orders each day. There are HVAC techs, electricians, plumbers, painters and then maintenance techs. They oversee all the preventative and corrective maintenance in the building like air conditioning, heating, plumbing and installing lighting, automatic doors, freezers/fridges, clogged toilets/sinks/showers, patch and paint walls, fire systems, elevators.... a lot of stuff. I want to read up more on how to do some of these things (the basics) and how they work (again, the basics). There is no "building maintenance for dummies" unfortunately, does anyone have any suggestions? I would like actual books instead of websites, although websites can be helpful. Thanks in advance for any help!

It's 98 outside and the A/C just went belly up!

damiano99 — Wed, 21 May 2008 09:16:32 -0800

Our home A/C unit is dying. What next? The other day we came home and our house was 86 inside even though we had the therm set for 75. We called our normal a/c guy and and he came out and said that the main unit which normally holds 6 pounds of freon, only had 2 in it. He suspects a leak in the main coil. According to him we could replace that for about 900$ but the kicker is that the a/c unit is 22 years old and he believes it has little life left in it. His opinion was that we could spend 900$ now and see how much longer it goes but that it would be better to spend the full 5500 now for the new 4ton unit. He claims the new unit would also be 30% more efficient and give us 15-25 years without problem. He is suggesting a Goodman.

I don't doubt that the unit is old and creaking. It makes the wierdest noises all day. But up to now it has worked. Not to mention that last year during a storm we lost one leg of electric coming in and it nearly burned out the motor with all the restarting on the single leg of power. However, I'd rather not drop 5k on something I don't have to.

Is there another way to do this? Is it just better to do it? We're totally neophytes in this area and need any and all advice. Thanks.

Furnace vents net to sandbox. Is this bad?

winston — Sat, 26 Apr 2008 09:50:23 -0800

High-efficiency gas furnace installed where previously there was mid-efficiency. So it vents straight out the wall while the old furnace used the chimney. The vent is right next to the sandbox. How bad is this? Tiny yard -- not much other space for the sandbox. It's either keep it or get rid of it.

Of course, during the peak months for sandbox usage, the furnace is rarely used.

It's in a corner (between the house and the wooden fence) so a little more enclosed than if it were in the middle of the wall.

The kids are 4 and almost 2.

A sandbox is one of their favourite things in the world and they can use it for hours at a stretch.

Cost for a new hot water oil burner/furnace

coffeefilter — Wed, 02 Apr 2008 23:53:50 -0800

(Oil Heat) - Getting a new oil burner / furnace. (1) How much should it cost, including installation, for a new oil furnace that's at least pretty good/efficient? (We've gotten one estimate, so far, for $10,000 (!) $11,000 for antifreeze pipe system.) What's the cost for the equipment vs cost of labor? (2) The $10K was for a System 2000. Is the System 2000 really that good? Anyone have one? How much did it cost? How much did it reduce your heating bills? 1700 square feet, hot water base board.

Are we getting ripped off for basement HVAC work?

crunchtopmuffin — Wed, 12 Mar 2008 19:31:06 -0800

Home HVAC filter: Help us figure out if we're getting ripped off! We were quoted $800 for some HVAC work that needs to be done for finishing our basement; is this a reasonable amount? My husband is acting as the general contractor for finishing our basement, which is approx. 600 square feet. He just hired a guy who was recommended to us as an HVAC "expert" (as in he works for an HVAC company during the day) by someone we trust. We initially got a good feeling about this guy, and we went with him without getting other estimates because we're eager to get this work done. (I know, I know, not the best decision.) We hired him off the books and he quoted us $800 for the following work: From the main trunk in the basement ceiling, he ran two 15-foot lines with a single register at the end of each. He also cut into an existing line and added two registers. All of this is occurring between the floor joists in the ceiling of the basement. The price sounded reasonable to us, but it turns out that it will only be about 4-5 hours worth of work, which has made us wonder if perhaps we're overpaying. Of course, we assumed that since he's doing this work off the books that we'd be getting a deal.

Anyone have any idea if this is a reasonable amount to pay? Anyone who has experience with HVAC subcontractors or who is an HVAC subcontractor, your input is greatly appreciated!

My heating system: just fine or time bomb?

a22lamia — Thu, 20 Sep 2007 13:12:31 -0800

My forced hot air system has no return ducts. Instead, cool air falls directly into the basement, where there's a filtered intake on the side of the furnace. Are my life, health, and or selling prospects at severe risk? You should also know that the hot water heater is right beside the furnace, though on the opposite side as the intake. Both are oil burning. Also, I live in Massachusetts, and plan to sell my home in about a year. The place is about 1200 square feet, and I've lived in it off and (mostly) on my whole life... so I've made it this long!

Will no return ducts cause my home to fail an inspection, or cause complications with the sale? In the mean time, how great are the risks from combustion fumes, dust, mold etc. from my basement?

The highly reputable firm who I am confident will do a first rate job installing the return ducting, has given me a rather expensive estimate. If I put it off, or opt for second or third rate, am I really just postponing the inevitable?

Replace HVAC now or later?

commander_cool — Tue, 07 Aug 2007 11:24:47 -0800

Ten-year old air conditioner, busted compressor. Get a new compressor, or replace the whole thing? Replacing the compressor will cost $1400; replacing the total HVAC will cost $3500. Allegedly, the compressor will get me five years more life before the whole thing goes out, while a new HVAC will last fifteen. If those numbers are accurate, and I'm not getting wildly overcharged (I'm in the DC area of the US), then I'm inclined to get the compressor, since my discount rate is greater than 11% (I'd rather spend $3500 in 2012 than $2100 now), but I'd like the collective wisdom of MeFi to let me know if those numbers are accurate. Also, whether those prices are reasonable enough that I shouldn't risk my girlfriend leaving me for someone with a working AC while I hunt around for a lower price.

Building codes nickle and dime server room cooling and me

clarkie666 — Fri, 03 Aug 2007 09:32:34 -0800

Can anyone help or point me in the right direction as regards CA building codes in relation to server rooms and cooling or how do you accommodate this if you are too small to need the big company solution. Our servers are stored in a closet room rather than a dedicated server space, which runs off the main AC. The building AC is switched off during the weekend, which even with the server closet door open, results in temps that a little high for my liking.
Now the simple solution would be to drop in a standalone AC unit in there, however my boss knows 'something' about building codes as it relates to enclosed spaces which require separate or dedicated cooling (i.e. server rooms) and even shoving in a small portable AC unit would officially send us down this this path, ergo big time costs around all that a big company server room would entail, i.e. fire suppression etc.
Can anyone point me in the direction of the code or where to get started to understand this? We are in California, and it is not an option to get the owners to leave the AC running in our space. Thanks all!