With a trend in ‘going green’ many homeowners have started to invest in more energy efficient appliances, which save money and conserve energy, and have started making other steps toward preserving the environment and spending less money while they’re at it! Most people consider upgrading their insulation in the winter, but if your insulation needs to be upgraded now, doing so can save you money in energy costs in the summer as well by keeping cool air in and hot air out.
If you’re not quite sure whether or not you should invest in upgrading your insulation, the U.S. Department of Energy (DOE) offers a handy formula for calculating the benefits of upgrading.
Thankfully, I have simplified this formula so that its easy enough for pretty much anyone to use. You’ll have to start by doing a little bit of research online or over the phone to fill in parts of the formula. After that’s done, it just takes a calculator and a few minutes to figure it out.
Here is the formula the DOE provides: (Ci x R1 x R2 x E) ÷ (Ce x [R2 - R1] x HDD x 24)
...And, so you can actually use it, here’s what all the variables stand for:
Ci: The cost of the insulation you’re considering (in dollars per square foot). If you’re making this a DIY project, this includes the cost of the materials, supplies, and any rental equipment you need. If you’re paying to have the work done, use the estimated cost from the contractor.
R1: The R-value of the insulation you currently have in the attic.
R2: The R-value of the insulation that you want to upgrade to.
E: The efficiency rating of your heating system/cooling system. How well your HVAC system heats or cools your home plays a major role in how much you’re going to save with an insulation upgrade. So, the less efficient your system is, the more money you’ll save each year by upgrading your insulation. If you don’t know the specific energy efficiency rating of your particular heating system, try calling your utility company or HVAC contractor. If you can’t find out from them, the DOE offers the following general suggestions: oil and propane furnaces, 0.6 to 0.88; natural gas furnaces, 0.7 to 0.95; electric, 1.0; heat pump 2.1 to 2.5.
Ce: What you’re paying for the energy you use (in dollars per British thermal unit (Btu)). To get this number, divide the actual price you pay for the fuel you use (electricity, gas, etc.) by the Btu content of that fuel. You can find the price you’re paying on your utility bill or by calling your utility company.
The Btu content of various fuels is as follows:
No. 2 fuel oil = 140,000 Btu/gallon
Electricity = 3,413 Btu/kilowatt-hour
Propane = 91,600 Btu/gallon
Natural gas = 103,000 Btu/cubic feet or 100,000 Btu/therm
HDD: This stands for heating degree days, which is a standard method for determining how cold a specific geographic location is, and how much demand there will be for heating. It’s determined by the statistical average of the number of degrees that a day’s temperature falls below 65 degrees Fahrenheit, which is considered the temperature at which a building needs to be heated. The higher the number of heating degree days in an area, the more demand there is for heat, so the greater the savings will be from an insulation upgrade. You can get your area’s HDD number from your utility company or off the Internet.
24: Hours in a day, used in this formula to convert HDD from days to hours.
This formula specifically determines how much you’ll save by upgrading your insulation in the winter time, but keeping cool air in during the summer months is equally as important as keeping cool air out in the winter months. Plug in your information to figure out whether or not it is a good idea to invest in an insulation upgrade this year.
For the original article from Inman News