Heating A New Addition

By Author: New Jersey Home Inspector Michael Del Greco
Total Articles: 21
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Heating a New Addition

Submitted by: Michael Del Greco, New Jersey Home Inspector Lic GI 0121, President of Accurate Inspections, Inc, a New Jersey home inspection company

Putting an addition on your home, such as a bedroom or kitchen, is very exciting. It often affects your attitude and comfort level and can truly renew your spirit. One consideration when adding to your home or when creating a new living space from a previously unused area, such as a porch, basement or garage, is the extra heating that will be required.


Your current heating system is probably sized for your current living situation, whether the unit is original or is a replacement. There has probably not been any considerations for a future addition.


The first thing you need to do is assess your current heating situation. A general rule of thumb for heating requirements is that 40 to 50 BTUs (British Thermal Units) are required for every square foot of living space. So, determine the square footage of your current living space (before the addition) and divide it by the 40 to 50 BTUs. This, of course, will depend on the ...
... type of construction and geographical location.


To figure out how much more you would need, assuming what you have is enough, simply add the square footage of the new living space to your current number. When you have this total, you can figure out the amount of BTUs you\'ll need for the addition.


You may be able to use the same input size heater if you buy a more efficient one. If you replace a typical heater that is 60 percent to 70 percent efficient with a heater that wastes just 5 percent to 10 percent of its heat/fuel, and if it includes an outside air supply for combustion, you could buy a heater sized at approximately 25 percent to 35 percent fewer BTUs for every square foot of living space. More effective energy improvements may allow you to reduce the size even more.


Heater efficiency is based on burner efficiency, transmission of losses to the heater exchanger or boiler and flue or chimney losses. The quantity of heat lost up the chimney is rarely discussed by utility companies or fuel suppliers. However, it is significant. Approximately one-third of all heat generated by a gas-fired unit goes up the chimney. Oil-fired appliances have 5 percent to 15 percent more waste. However, oil costs less than gas to purchase.


When the distribution of air is from an existing situation, additional ductwork may be needed. The farther you travel from the source, the smaller the ductwork needs to be to increase/maintain adequate air velocity. Additional fuel and ductwork costs should be factored in. In some cases you may have to redesign some or all of the ductwork to assume equitable distribution.


Before you begin a new addition, consider the changes that will take place. Don\'t get discouraged, because these calculations are not so difficult to do. The half-hour you may put in will be well worth the years of enjoyment you will get from the new living space.



Information provided by Michael Del Greco, New Jersey Home Inspector Lic. GI 0121, American Society of Home Inspectors Member 102273, Pesident of Accurate Inspections, Inc. A West Paterson New Jersey Home Inspection firm.