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| My north Florida home was built in the 50's or 60's. It is mostly cinder block with a gable roof, one story. Unfortunately, the previous owner was a DIY'er who believed in shortcuts. The home is about 1200 sq ft in the main part but with additions the total area is about 1600 sq ft. One addition used to be a carport and doesn't have any insulation in the ceiling but I think it has some in the walls. The other addition (I believe) is the opposite. I haven't had occasion to confirm that 100% but that is my best guess based on some of the repairs I've had to do. The main part of the house has fiberglass insulation in the attic. The additions are a combination of stick built and cinder block. There are soffit vents all the way around and two vents (not sure what they're called) about 3 ft long near the peak of the roof. Being a big guy combined with the way the trusses are built and where the ducts are run in the attic, I can't get up there. I can see that at one point there was a vent or a fan in the gable above my bedroom but it is gone and has been covered over with vinyl siding but the plywood was not patched. There is currently no attic fan. My A/C unit is about 30 years old but has had some serious service/parts replacement done to it so I expect it to last a few more good years. As you might imagine, our electric bill is pretty high in the summer. I'd like to make some insulating upgrades but I'm not sure where to start. I don't want to pour a huge sum of money into it but we'll probably be here 5-10 years so an investment in insulation would have time to pay for itself (I would think) before we sell. The additions get extremely hot during the day from about April - December so I was thinking of starting there but I was also thinking of adding a powered attic fan on a thermal switch (or maybe solar since the hole is on the south side). Not sure what would provide the most bang for the buck. Thanks in advance for any suggestions. |
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| If your AC unit is 30 years old it's probably has an 8 SEER rating. Purchasing a new system,even with the present minimum of 13 SEER,should in theory result in a 38% reduction in your electric bill. I think you need to have your duct work evaluated as most likely it's the original and may have problems contributing to your high electric bills. I don't think you'll get much help with an attic fan (some studies show they actually suck air conditioned air from the rooms below). Therefore, sounds like it's the 400 or so square feet of the converted carport that is your major concern. If there's attic space above the carport than insulate it. If not I can't think of any easy/inexpensive way to insulate it. |
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| Adding insulation to an attic is the most cost effective improvment. I like batt insulation, but you may need to use the blown in type if you have a very constricted area. Powered attic fans can cause more harm then good if the attic is not properly vented. A negative pressure condition can be created if the soffit vents cannot supply enough air to keep up with the fan. This could cause conditioned air to be sucked up into the attic. You may be better off with a passive turbine vent. I am impressed your AC has lasted 30 years in the Florida summers. I know you have have spent money repairing it, but consider replacing it soon. You could cut your AC power bill in half with a more efficient unit. |
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- Posted by neohioheatpump (My Page) on Tue, Apr 10, 12 at 11:57
| Blown in insulation works great. I've also done fiberglass batts. Insulating an attic can be a DIY if your carefull not to fall thru your ceiling. You might save alot of energy with a new unit and it might pay for itself in a reasonable amount of time. I like highest efficiency single stage units of 15 seer myself. |
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| Attic ventilation fans are generally a bad idea. They use energy and if not carefully balanced, they can suck conditioned air out of the house through perforations (leaks) between the living space and attic. The rules for sealing your house and insulating are different in the humid South than in cooler and drier parts of the country. Some good places to look for advice are probably land grand universities in that area, University of Florida, Louisiana State University,�. In addition, http://www.buildingscience.com/ has a lot of good information for hot, humid climate building. Last, but certainly not least, consider hiring an energy rater. Do a little research first. Interview more than one on the phone, but asking them what in general they would do with a home like yours and if they know of any local rebate programs that would pay for improvements or their services. http://www.resnet.us/trade/home-energy-raters-hers-raters. They will be able to tell you a lot more when they are in the house and do testing. To summarize, when homes were not mechanically cooled, a vented attic made some sense. Now, with older-style homes that have added AC ducts in the attic, it makes more sense to seal the attic and spray foam the underside of the roof deck with low density foam insulation. You no longer have to deal with all the leaks between the house and the attic and your ducts will be cool and the leaks in them less relevant. Your ducts are now outside the envelope of your house so when the leak your are blowing air outside. That air is replaced through leaks in your rooms. Beyond being wasteful, it can cause condensation in places where you don�t notice it and you get mold growth. Lastly, if you want efficient AC and want to get rid of those pesky ducts to get rid of their pressure differentials forever consider installing heat pump mini splits. You will have effective zoning with them too and that can save you a bundle depending on your lifestyle and the layout of your home. |
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- Posted by energy_rater_la (My Page) on Tue, Apr 10, 12 at 13:22
| someone needs to get into your attic and look around. the best scenerio would be to hire someone who can advise you as to your best options for your specific home. there are many energy raters in florida, you could make some calls and hire an independent third party. I don't know how it works with BPI, but as a Resnet energy rater we do inspection & testing for air leakage into the house, and duct leakage. there are two seperate testing dates, prior to any upgrade, and once upgrades are completed. the first to establish a baseline for your house, and advise on upgrades. the last is to verify that house leakage, duct leakage and any issues that were addressed accomplished what they were bid to do. as your house has both cinderblock and stick frame construction, and age of house I would suggest that you have considerable leakage. blower door & duct testing would trying to heat and cool a leaky house is expensive. if you can get a foam company that has worked with most of our house leakage is from the living to the cost of foam is higher, and you should keep in mind that as to where it leaks in the walls of the house, the best of luck. |
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