Basement and garage ceiling insulation?
Hi.
Currently both my basement ceiling and garage ceilings are NOT insulated. Do you recommend that I insulate them? If so, what R value should I use? I have a single car garage which is attached to the house. The space above the garage ceiling contains my central air conditioning unit/machinery and can be used for light storage. The garage , attached to the end of my cape style home, shares a wall with my living room and kitchen and one up stairs bedroom. The shared wall with the bedroom, is sheathed with that brown Celotex stuff and insulation (R-13) behind that. The basement simply has my laundry room (with unfinished walls) and a workshop (that has finished drywall walls with insulation behind them). The floor of the basement is bare concrete. Thanks.
Replies
Depends how you want to modulate natural heating and cooling. I insulated both my detached garage and basement, both are more comfortable (year round) now.
I have a 4-year old house with R-38 ceiling, R-19 walls in western Montana. The 6" concrete wall basement was uninsulated, mostly below ground, and only heated by duct loss, the gas water heater, and dryer use. To make the basement more comfortable for lifting weights and using a stationary bicycle trainer I glued R-6 beadboard around the perimeter then built an interior 2x4 wall with fiberglass insulation and sheetrock. Before the insulating job, basement temperatures would drop to 54 in the winter (remember the ducts were warm), and rise to 65 in the summer. Now it varies from 58-62, which is really good for the exercise area.
The best part is that I cut 30% off my energy use last winter. That's 30% of energy, not just dollars, and energy costs are rising. That 30% is normalized for temperature differences so it wasn't just a warm winter that caused the savings. Here's a (long) link to the details on my web page:
http://www2.umt.edu/Geology/faculty/sheriff/Sheriff_Vita_abstracts/Basement%20Insulation%20Energy%20Savings.htm
Thanks Steve. Looks like you've done some serious homework. I'm most likely going to install faced fiberglass in the basement ceiling R-19. With the 2x10s there and this 6 1/2" deep insulation, I'll leave an airspace above the insulation, which is good.
Would you know how do I calculate which is cheaper, gas or electric heat? Do i get that from looking at my gas bill and electric bill and look at the per unit rates? Or is it more difficult than that?
"Would you know how do I calculate which is cheaper, gas or electric heat? Do i get that from looking at my gas bill and electric bill and look at the per unit rates? Or is it more difficult than that?"You start there, but that only gives up the energy cost. But you have to look at the incremental cost. On my gas bill there is a fix cost and 2 cost that are proportional to usage. One is the purchase cost of gas and the other is the cost for local distribuion system. The electric has a fixed cost and a usage cost. However, except during the summer, the unit cost does down in 3 steps with increasing usage. You need to know the efficient of converting that energy to BTU's.For gas it can be 80-95%.For resistive heating it is 100%.For heat pumps you get about 3-5 times the heat out for each watt in, but that varies with tempature.