To use the following charts, you must first figure out your actually cost per unit of electricity, gas, propane or oil. The actual cost per unit includes all taxes and delivery charges added to the actual cost of the fuel. To do this you would take the total of the bill and divide it by the “usage” listed on the bill. For example:

Ohio Edison – Total Bill $275.13

Kilowatt Hours Used       4,433

Cost per KWH                 .062

Dominion –  Total Bill  $74.59

MCF Used                      6.3

Cost per MCF             $11.839

Convert to CCF             $1.184

It is the same calculation for propane oil oil, just divide the bill by the total gallons purchased to get the true cost per gallon.

Now that you have your price per unit of fuel you are ready to use the chart. Let’s start with the first example. You currently have a furnace that predates 1992 (which is probably in the 55-65% efficiency rating). You are considering a new furnace and don’t know what efficiency to get. If your gas cost per unit is $1.20 you would go to that column at the top of the chart in the gas section. Then you would go down to your current efficiency row (we’ll use 60% for this example). You can see that your cost per million Btu’s of heat is $20.00. Now if you go down to the 80% row you will see that that cost per million Btu’s drops to $15.00, and if you go down to the 95% row you will see it drops even further to $12.63 per million Btu’s. This is a $7.37 savings per million Btu’s over your current furnace.

The same principle works if you are considering replacing an oil furnace with gas. Let’s go with the assumption that the total cost of a gallon of oil delivered to you is $4.00 per gallon and your cost of gas is $1.20, your current oil furnace is 65% efficient and you want to get an new 90% efficient gas furnace. First go to the $4.00 column on the oil chart and the 65% row – you will see that your current cost per million Btu’s of heat is $44.37. Now go to the gas chart to the $1.20 column and the 90% row – you cost per million Btu’s of heat is now $13.33, which is a savings of $31.04 per million Btu’s of heat.

More complicated is the conversion of a fossil fuel to electric heat pump. First you have to find out what the COP of the unit you are considering is. The higher the efficiency of the heat pump the higher the COP, but other factors such as single stage or two stage heat pumps and what unit (such as an air handler or standard furnace) you are connecting it to. All these make a difference in the COP rating of a heat pump. For this example we will consider that you currently have a 90% efficient gas furnace and are considering getting a heat pump to handle the air conditioning needs of your home with the extra bonus of reducing your heating costs during the winter. We will assume that your gas cost is still $1.20 per unit and that your electricity is $.10 per unit. The heat pump you are considering is a 16 SEER two stage unit that has a COP of 300%. Go to the $1.20 column of the gas chart and the 90% row and you will find that your cost per million Btu’s of heat is $13.33. Now go the the $.10 column of the electric column and the 300% row and your cost per million Btu’s of heat is $9.77.

There are more considerations when determining which unit(s) you should choose. All gas, propane and oil furnaces use electric to power the unit, and run the blower. This is not included in the costs in the charts. A new furnace equiped with a DC or variable speed blower can save up to $400 per year on the electricity needed over a furnace with a standard blower. New furnaces and heat pumps also come in two stage or variable stages of operation, which means the unit ramps up or down in capacity as required by the weather. All these options may cost more when you purchase them, but they will save money in the long run. Choosing whether you get these features or not depends on how you use your systems, whether you plan on staying in your house for the rest of your life or only a couple of years, etc. Your heating and air conditioning representative is valuable in helping you understand these choices.

Here at Dieter Heating & Air Conditioning, we strive to make sure that you have the optimum system for YOUR home and YOUR lifestyle. We give free estimates and will take as long as needed to make sure you understand all of YOUR options, not what WE want you to have. Just give us a call if you want to see what you can save with a new heating and air conditioning system.