Ask MetaFilter posts tagged with hvac

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!

Is it me, or is it a little warm in here?

colgate — Sun, 08 Apr 2007 19:38:13 -0800

What form of energy is used to heat a Wal-Mart, Home Depot or Costo store, and how much does it cost per month in the winter? Each time I walked into Wal-Mart this winter, it felt 75 degrees inside. Many times, it was 25 degrees or colder outside. A Wal-Mart Supercenter is easily 100,000 sqare feet (with high ceilings to boot). How much does it cost them to keep such a massive space heated 30-50 degrees above outside temperatures 24hrs/day for a month? And what are they heating the place with?

I think my air conditioner is dying. Help me not get Rheem'd.

LuckySeven~ — Tue, 13 Mar 2007 09:22:36 -0800

Last spring my husband and I noticed that a small puddle of water would form on the garage floor every time we used our central a/c for more than a few minutes. We had a local a/c guy come out and he told us the pan was leaking and needed to be replaced. He quoted us around $2,000 which I thought was extremely high considering he'd done the exact same job a year previously for our neighbor (who has the same model house and, incidentally, recommended this company) for $400. We then asked him how much it would cost to replace the central a/c entirely since the unit was over 17 years old and probably on its last legs anyway. He went out to the backyard, took one look at our trusty old Rheem and said, "$8,000." Wha-wha-what?!

We know next to nothing about air conditioners, but I immediately went to work researching a/c brands online and getting quotes from other local companies. None of the four companies who came out did any duct tests or asked any questions about problem rooms (we have two -- the master bedroom which, due to it's location, gets extremely hot in the summer and very cold in the winter and the living room which stays relatively cool in the summer and downright artic in the winter). The first guy's quote was the "cheapest" at 8K -- he said he'd basically replace the Rheem with a bigger, more current model -- and the most expensive quote was from a company that does a lot of heavy advertising in our area and claims to be number 1 in customer satisfaction: $12K for a top of the line Trane with climate control and some kind if allergy filtration system. Needless to say, we were in serious sticker shock. We survived last summer's heatwave by diligently cleaning the outside unit and crossing our fingers; the puddle in the garage got bigger, but we made it. Fast forward to now. We still have a decision to make, but I need some serious advice before proceeding.

Our house is a small 3 bed/ 2 bath (under 1300 sf), one story tract home in the Central California 'burbs. Can these quotes be right? What kinds of questions should I ask the contractors? Why do they just take a few room measurements and toss out a quote without doing any duct tests or asking us anything? Some of the guys don't even take measurements, they just look at the current unit and suggestion something bigger. I've read that buying bigger without doing the proper tests can be a mistake -- especially when dealing with problem rooms. Asking friends and neighbors hasn't worked out so far; most people we've asked do very little research and pay what they're quoted, just like that. Since this is such a huge chunk of money for us, we're trying to be very careful. Any help and/or advice would be truly appreciated. Thanks!

P.S. The guy who gave us our first quote of $8K claimed he would be saving us money by *not* dealing with city hall and writing the job up as a "repair" rather than a replacement whereas the "expensive 12K" guy emphasized that he *would* file all of the proper contractor's paperwork and perform the job according to the new "rules" so that we wouldn't have any trouble when if/when we decided to sell our house in a few years. Can anyone break this down for me in layperson language?

. . . building a home network so cool, it's HOT.

datacenter refugee — Sun, 14 Jan 2007 00:24:27 -0800

Not-My-Walls-To-Cut-Through-Filter: Anyone have experience running Cat5 through HVAC ducts? I just moved into a space-limited Row Home and would like to keep my rack of various equipment (dvr, X10, security, nas) out of sight and earshot. The basement looks to be ideal for this purpose - but with plaster walls and new hardwood floors I can't in good conscience drill to run cable to the first and second floors. New windows eliminate the possibility of external-house runs, and the existing cableTV drops were drilled through the houses external brick and grometted. The only option seems to be the existing heating duct. There is a straight vertical duct-work run to all floors that terminates in the basement roughly 8' from the furnace itself. My non-plenum rated cable says it has a max operating temp of 140°F.

My question(s):

- Has anyone ever done this?
- Did the cable (or even cable jacket) melt?
- Would a 70+ year old duct run have built-in obstructions like a grate or something to stop urban rodents?

Thanks in advance!

Home furnace timing question

Salvatorparadise — Sat, 11 Nov 2006 17:49:14 -0800

I just moved into a house that I bought, and the heater makes this 700 square-foot house nice and toasty, but the timing seems off. First something comes on, it makes a humming, sounds like a motor, but no air is coming out yet....that goes on for a minute or two, then the igniter clicks on and glows for about a minute, then flames come on for 3-5 minutes, then the fan comes on and blows heat up throughout the house. Inspector said... The inspector said it has a timing issue....is this the case, what is likely the problem, and is this an expensive fix...?

Also, is this that big of a deal? It would seem, for fuel conservation purposes, not to be very efficient to have the flames on for a few minutes with no fan blowing...because once it blows it does so for only a few minutes before tripping the thermostat and shutting off...

i'm just trying to get a handle on how much it might cost to get this thing timed right.

the heater is a 1994 Fraser-Johnston.

Help me make sure I'm not getting scammed...

twiggy — Fri, 13 Oct 2006 19:16:36 -0800

BrrrrrFilter: It's gotten cold here in Chicago and my heater appears to be broken. Google didn't help me much probably because my knowledge of HVAC is weak. Help me find out quickly if I'm being ripped off? I feel like I can trust this company, I've had them out here before, but I just want to be sure.

I'd start my heater up and the fan would spin up briefly (a few seconds at most) and then just stop. The flame didn't seem to light up.

He says it's a problem with a gas valve in the system, but because it's an electric system, this whole set of things (3 things: valve, ignitor and something else) need to be replaced. Total cost for these materials: $489.

I asked how this could have broken, and his explanation was that since it's an electrical system, if condensation got in there it could kill the thing. This story actually jives with something that happeend early this summer when I moved into this place (which I recently bought): The A/C was not working and the previous repairman found lots of condensation in the unit. I just didn't know it wrecked my heating ignition unit, I guess, because why would I be using the heat in June?

The previous repairman, by the way, did a bang up job adding some wrapping around all of my piping etc to prevent future condensation.

So.. is $489 a ripoff? Does this "if you replace the valve you gotta replace it all" thing seem like a sham?

In this house, we obey the laws of thermodynamics

winston — Sat, 29 Jul 2006 19:46:45 -0800

What can we do to get more air from the air conditioning (and the heat in the winter) to the back of the house? 100-year old house. An addition was built about 25 (?) years ago. The addition is about 40% of the house. It was built without a building permit and with some, um, interesting technique. Very little air comes out of the vents in the addition. None of the ductwork in the addition is accessible without tearing out the floors.

We have had the ducts cleaned, and an annual checkup for the furnace and air conditioner (they're both in good shape). The HVAC guy says that he could put a more powerful fan in the furnace for a few hundred bucks but he doesn't know if that will help (the furnace is newer than the addition, BTW).

Searching AskMe brought up this old question about duct sealing (with a thumbs-down answer) -- but I don't even know if the problem is leakage or blockage.

Right now running the air conditioner only on days when the outdoor temperature exceeds 30 degrees C triples our electricity bill for July and August and it doesn't get the temperature down past 26.

Looking for a

johoney — Thu, 20 Jul 2006 09:16:08 -0800

8 unit condo in Jersey City needs an energy (HVAC, heating) consultant to look at our boiler and heating system and advise us on how to lower our heating bills. We are keen to consider green options but economy is the main criterion. Thank you for your recommendations and advice. In our building we are currently collecting $$ to replace the oil boiler that fires our central heating. I'm a little concerned given the price of oil and want to be certain that our building is optimized for energy conservation. Do you know any consultant/expert who can survey our building and heating system and make recommendations?

Its an old building, the thermostat is in the hallway, the radiators are vertically integrated with no control valves. Which means that in Winter some apartments are overheated and leave windows open and some are cold.

We'd certainly consider going as green as possible and (before you mention it) have already looked at revofuel though its a bit young at this point in terms of available resources. Thanks for any recommendations on where to find the expert we're looking for.

Furnace replacement - what to ask the contractors?

gwenzel — Mon, 17 Jul 2006 18:03:00 -0800

I'm having three HVAC contractors come to my house tomorrow to give me estimates for replacing my gas furnace. What should I look for to identify a "reputable" contractor, and what questions should I ask? Just for clarification, I'm replacing a 15-year old gas furnace that has a cracked heat exchanger. I'm probably going to get a two-stage, variable-speed-fan furnace. What questions should I ask the contractors, and what information should they be gathering from me? I know that they're supposed to do a "heat loss calculation" but I have no idea exactly what that is or how it's done. Any advice from mefites that have gone down this road (or are HVAC contractors) would be appreciated. Thanks!

water on air compressor

stevejensen — Sat, 23 Jul 2005 15:40:49 -0800

Home HVAC filter: a/c compressors... I have a 4 ton York A/C compressor outside, am I helping it or hurting it by spraying cold water on the surrounding cooling fins on a 100 degree day?

Air conditioner coils

mecran01 — Wed, 15 Jun 2005 09:11:38 -0800

We had our furnace worked on by a local guy who has a good rep. We mentioned that our air condition had been icing up, and he said we should get the coils cleaned. $300. The thing is, the compressor unit thingy is outside, it's only a year old, and I can access it with a hose myself. Am I misunderstanding what he's talking about? Should I do this myself? I hear conflicting reports on the internets, stuff like "he hauled out bags and bags of crud." I am lost and confused. Is he talking about cleaning something inside the main furnace unit in the basement? Yes, I will ask him for more info, but wanted to know what your experiences are. Thanks.

Trane heat pump $3000?

jsavimbi — Tue, 14 Jun 2005 12:59:17 -0800

I've just been quoted $3000 to install a new outdoor heat pump unit and remove the old one. New thermostat included. Does that sound like a lot of money?

Question number 12913

eurasian — Mon, 13 Dec 2004 12:45:49 -0800

Well, our new old apt (it's new to us, but it's old) has no range hood. Looks like the previous owner decided to make a HUGE pass through. What solutions/options do I have (besides some sort of bizaare way to hookup an ordinary rangehood). Do the somewhat reviled ionic breeze / ionic cleaners work well enough to clean the air? It's a 600 sq ft apt.