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Old 03-22-2015, 04:50 PM   #6 (permalink)
rmay635703
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Quote:
Originally Posted by Sven7 View Post
I just moved to a rental house and the water heater and furnace are super inefficient. A guy at work recommended the fiberglass wrap. Has anyone here tried that? How well does it work? I'm considering doing it, and probably turning the heat down as well.
Actually there are 2 key factors, reflective insulation (aka reflects infared) and then the actual R value.

If you don't have a lot of space and are looking for aesthetics fiberglass insulation w/ the flashing on the outside is the best but the cost is now rather high for the savings (AKA $30 on up)

If you do the purpose made wrap make sure the insulation value is AT LEAST R11, lower wraps (like the R3.3 at menards) are not only cheaper but also not very effective.

If you are cheap and can find cheap traditional bats they work almost as well or sometimes better depending on how thick, etc.

My father used to be able to get the "Astronauts" insulation (reflective bubble wrap) very cheap and wrapped the last one in that. It only has an R value of 6ish but because its reflective you get some added benefits, also if you wrap the thing in a special fashion and leave a slight air gap you can get R14 or Higher.

Sadly now days the reflective bubble wrap is very expensive (but you do get a fair amount of the stuff)

Ah well, we settled on a squatty self cleaning unit (because it fits more easily and was on the lower end) Was $359 and we get a whopping 11% off, still a full hundred cheaper than the cheapest but it at least meets needs.

All the water heaters we looked at were only 59% efficient and had a cost of operation of about $277 a year.

I tried to convince my father to get a $600 70% EFF unit but it did not have self clean and was tall (we would have to cut stuff), payback period was a little over 4 years which was reasonable.

The 81% EFF units were all $1000+ (apparently I misread) and required additional "stuff" to function making them a deal killer, payback was poor.

Ah well, so much for appliances getting more efficient over time
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