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why does my house cool off so fast?

Posted by rileysmom17 (My Page) on
Mon, Dec 11, 06 at 19:29

I purchased a home built in 1985. It is 1700 sq down, 1300 sq ft up with a cathedral living room and foyer ceiling. The basement is 1600 sq ft. A small area of the second floor is built out over the garage. I installed Schuco double-paned Corona 4000 windows (krypton in most, argon in the rest) and Precision doors (argon) throughout. I leave a few windows cracked on each floor to keep some air flow. Last summer when I had all windows and doors shut during a very hot week, we definitely suffered from stale air syndrome. So I assumed that the house was reasonably "tight". However, I still notice after the thermostat cycles to "away" that the house will lose 6 degrees (from 70 to 64) in about an hour. Is this good, average, or poor heat retention? What can I do to improve it? Right now I have no window treatments (building the budget), that is a variable open to manipulation. More attic insulation (I have the fluffy white stuff), more basement insulation? I have a 14 SEER heat pump upstairs, 14 SEER AC and 95% efficiency furnace downstairs (is there such as thing as 98% efficient? it is at least 95% efficient) and my average monthly electrical + gas utility is $160, which seems to me to be pretty good. I live in North Carolina. Thanks for your thoughts.


Follow-Up Postings:

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RE: why does my house cool off so fast?

Hello,
Close the windows. Add a fresh air heat exchanger, instead of leaving the windows open.

I have very poor insulation in the attic; Squirrles removed about 1/3 of the covering in the attic. I loose about 10 degrees in 2 or more hours, depending on the outside temperature. I consider this to be very poor heat retention. When I add insulation this winter, I expect to increase retention by 50%. This means loosing 5 degrees every 2 hours. If I could afford double paned windows, it would increase more. Since I removed incadessent lights, the temperature drops quicker.


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RE: why does my house cool off so fast?

I think that your R-value should be increased significantly.
R-19 walls and R-38 ceilings are common today, along with either Anderson or Pella double glazed Low-E glass, and Therma Tru exterior doors.

Solargary you can get a Hobo datalogger from onsetcomp.com these people are great, I just walk in and get what I need.

You might benefit from a slightly longer downrod on the ceiling fan.

I love the radiant heat with 12'6" ceilings (I have Hepex plus with transfer plates) however wood keeps arriving from heaven so I am compelled to burn it!


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RE: why does my house cool off so fast?

Reply to bushleague...Schuco windows out-rate pella or anderson and are better engineered; I believe Precision doors rate top in insulating capability too. Given that I cannot tear down my walls, it sounds like adding more insulation to the attic is a place to start. I was up there last night and I noted that I wouldn't be able to pile it deep in the perimetry because that would block off my soffit air flow - is this a typical issue? What type of additional insulation would you recommend?

Reply to solargary...I took a look at my 'cracked' windows in relation to the return air vents and had an A-Ha moment. I also threw another blanket over the house fan in the attic. Is there some kind of special blanket or material that can be thrown over attic protruberances to deal with heat loss? I thought about sacrificing my best down comforter to the job but decided it might be better used on my bed.


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RE: why does my house cool off so fast?

The Schuco windows look like a decent unit, however there weren't any ratings on their site which I possible overlooked, and are not rated by the NFRC. Are they Energy star rated (U factor <35)?

In a situation like your attic we install prop-up vents, a simple plastic or styrofoam channel that fits between your roof rafters in order to channel air upward to the ridge vent, and keep the roof sheathing dry. You don't want to block the soffit vents for this reason. HD had a deal on OC fiberglas batts where you can add to your existing insulation.


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RE: why does my house cool off so fast?

"Reply to solargary...I took a look at my 'cracked' windows in relation to the return air vents and had an A-Ha moment. I also threw another blanket over the house fan in the attic. Is there some kind of special blanket or material that can be thrown over attic protruberances to deal with heat loss? I thought about sacrificing my best down comforter to the job but decided it might be better used on my bed."

I have a whole house fan also, and built up a box around its perimeter made from 2 inch thick rigid foam board. In the winter I put a lid on this box also made from 2 inch foam board, and put a couple of rocks on it to make sure it seals down to the foamboard edges (high tech eh). I then throw some batt insulation over that. The foam board box seals up the whole fan in the box, and also keeps loose fill insulation out of the fan area.

Another notorious leak area is the hatch to the attic. I've seen studies that concluded that a large part of the total attic heat loss can come from a leaky hatch.

For other penetrations (like wiring, plumbing, can lights), I raked away the existing loose fill insulation, then used the polyurethane foam in a can (eg Great Stuff) to seal all the gaps. Its a bit messy, but easy. You have to be a bit careful insulating around can lights if they are not approved for direct insulation contact.

For the problem of increased depth of loose fill blocking the soffit vents, they make thin foam board "chutes" that you staple up the roof sheathing before putting in more loose fill. The chutes keep an air channel open. Home Depot type places sell them.

Bushleague -- I'm also a big fan of the Onset loggers -- I'm up to 3 of the 4 channel ones (don't tell my wife :).

Gary


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RE: why does my house cool off so fast?

I can see the soffit chutes, I always wondered what those were. So I think I need another row before I can deepen the insulation. My HVAC guy was tuning up my heat pump yesterday and I asked him to check the insulation depth, his reply was "kinda shallow compared to new construction and a little packed down from the work" so as soon as I can find someone I trust to handle the issues I will get on it.

Gary - have you ever heard of insulating your attic hatch with the Attic Tent? Awesome device. I have one, made a noticeable difference immediately because the upstairs air return is right next to the attic access, and the upstairs thermostat is immediately below both. www.attictent.com

Question re attic ventilation...I need a new roof, I have large side gable vents but no ridgeline vent. Roofers have suggested installing a "concealed" ridgeline vent. Now, my personal thermostatic problem is too-cold-in-winter, not too-warm-in-summer. Anybody have strong feelings one way or the other about adding a ridgeline vent and its effect on house temp at different seasons?


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RE: why does my house cool off so fast?

Don't rush out to get fresh air exchanger until you can determine you need one. The minimum air exchange accepted today is 0.25 per hour which works out to roughly 6 whole house air exchanges per day. Changes are your house is much higher than that. Most people immediately think additional insulation in the attic gives the most bang but that's not always true.

Fixing an air filtration problems will give you significantly better heat loss numbers that adding insulation. Contact your utility company and see if they offer discounted energy audits. I got an energy auditor to come to my house for $100. This included a complete heat loss analysis, blower door test, and recommended upgrades with ROI figures.

From here, you will know exactly what to do in what order given your budget. Some people will spend $300 insulating their attic as a first step to save money when $30 of caulk and foam sealant would have improved their energy cost twice over.

cellular shades will give you the most R-value for your dollar so go with those if it fits your decor/style.

Good luck!

BTW, what are the outside temps when your losing 6 degrees F per hour?


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RE: why does my house cool off so fast?

My thermostats are programmed for 70 between 6 am and 7:30 am. Thereafter they are programmed for 62. This morning at a little after 7 am the first floor was 71 degrees (on an independent thermometer which agreed with the thermostat). By about 8:10 it was 69 degrees. All doors and windows were shut and the outside temperature (according to my car) was about 47 degrees, not really very cold. I have a large number of large windows and two exterior doors are full-glass as well (hey, it was this way when I bought it). I have called my local energy company and left a message asking about an energy audit.

Below is what the Schuco window distributor has to say about them:

TPS Glazing with Superior Thermal Efficiency

Schco is the first U.S. window manufacturer to offer the TPS MAXX Glazing System, widely renowned in Europe for superior thermal efficiency. Designed to produce glass units of the highest conceivable quality, performance and durability standards, the TPS System delivers more superior insulating properties than most traditional spacer systems.

360 Non-Conductive, Flexible Spacer.
Metal glass spacers in other window systems act as thermal conductors - allowing heat to escape during the winter, and heat to enter during the summer. Schco TPS MAXX sealants do not conduct thermal energy. TPS sealants expand and contract simultaneously in response to temperature changes - eliminating sheer stress, which can cause seal failure in conventional units with metal spacers.

High Performance, Reflective Coatings.
Low-E coatings on Schco windows increase insulation value because they retain heat in the home during winter and conversely prevent heat from entering your home in the summer.



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RE: why does my house cool off so fast?

Hi,

"Gary - have you ever heard of insulating your attic hatch with the Attic Tent? Awesome device. I have one, made a noticeable difference immediately because the upstairs air return is right next to the attic access, and the upstairs thermostat is immediately below both. www.attictent.com"

Thanks for the link on the attic tent -- pretty neat.
I added a link to it from my webstie.

Gary


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RE: why does my house cool off so fast?

6 degrees lose per hour is almost disastrous and is speaking that your house is not tight. Whether the reason is with the windows only I do not know but as long as you are emphasizing on it let us start with this very path.

I am a building engineer and have 25-years experience with home buiding as well as with Schuko that is a very good name in Europe indeed.
A large number of large windows and two full-glass exterior doors may contribute to the fast energy loss problem but may not be the core of it.
You have done a good job installing new frames. I admire your professional (!)approach to Schuko merchandise quite well advertised by you above. Regrettably Schuko plastic frames are not always that good as their aluminium frames are. It is not only my professional opinion that their gaskets are sometimes not air-tight enough especially on turn-n-tilt frames.

Returning to your problem : First of all make a simple air-tight test starting from the windy side windows. You can do it alone saving money - see my e-mail to you explaining what might be done. A blower door test seems to me too costly and not imminent at this stage.
In case of a positive test for windows air-leakage let me know and we may discuss the remedy. Send to me e-mail with more details on the test result.


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RE: why does my house cool off so fast?

I will have an energy audit soon and I will post the results. It will cost $125 and hopefully I'll get my money back pretty fast. It has been so warm I think I won't make it back on gas! Valilzar it is almost never windy here and I couldn't figure out how to suspend my box fan from the roof :) ...so I think I'll wait for the pros and then get your opinion on their opinion.

I found the following technical info on Schuco windows (not much but...) the U-Factor is 0.22.

Also, I made the insulation-board box for my house fan as suggested by one of you...we'll see what happens to the duct tape at the corners the first time I turn it on in the summer! I must say it looks quite home-owner-grown-sincere-about-personal-conservation-efforts...I'll have to show it to guests!


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RE: why does my house cool off so fast?

Hi,
The audit sounds like a good idea.

I would very much like to hear what they conclude, and what you think of the whole audit process, what they actually do, and whether you think it was worth the fee.

Gary


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RE: why does my house cool off so fast?

Hi,
One last thought on the foam board box for the wholehouse fan.

The duct tape will probably work fine for a while, but it does deteriorate in a couple seasons. The next time you are up there, you might use a can of the polyurethane foam (eg Great Stuff), and put a bead of the foam in all the corners. This will glue the box together well, and also seal it against any leakage. The urethane foam is a great adhesive -- as you will find out if you get it on your fingers :)

Gary


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RE: why does my house cool off so fast?

Quote: "...it is almost never windy here and I couldn't figure out how to suspend my box fan from the roof :) "...... Such a pity that you couldn't do that indeed and in case you succeed please provide a photo :):):)
By the way, the proposed windows air-leakage test is for many years worldwide known in windy and not windy areas as the cheapest, fastest, non-complicated and reliable one (it has nothing to do with a roof fan - a simple desk-fan, hair-dryer, etc. would do). It seems that this test is not applicable in your case.

The 0.22 U-factor is OK and all the other information provided by you on the advantages of Schuko windows is also OK.

After receiving so many opinions/suggestions the idea for ordering an energy audit to professionals is the best one indeed ... apart of that, one may wonder whatfor people have to use this forum:)
Good luck!


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