Traditional • New • Hybrid
By George Harvey
People often ask about heating options, and what the best solution is. We knew about a number of developments, but information seems to come from all sides, with each touting its own solutions. Real clarity requires a disinterested approach, and there are many options to choose from.
We talked to Jake Marin, who is an energy consultant for the Vermont Energy Investment Corporation. Jake sees all sorts of housing situations in all sorts of buildings. One thing that becomes clear very quickly is that there is no single approach that fits all situations. Also, there is very often no single, best solution for any given place.
One traditional New England approach to heating is a hybrid. Many of us have a conventional heating setup with a backup in case of power outage or for remote parts of the house. The combination of an oil or gas furnace with a wood stove or two for backup is very common. Another common setup is having a conventional fossil fuel-based heater in one room and a pellet or wood stove in another.
When a hybrid system is designed with a view to cost and ability to function in a power outage, it can serve well for both. In today’s energy market, one of the least expensive heat units to run is a heat pump. Since heat pumps require electricity to function, a good hybrid system might add a wood stove, which can provide relatively low-cost heat from cordwood, as it is needed.
Heat pumps come in two basic types. One, the ground-source or geothermal heat pump, is super-efficient, but expensive to install, with the cost depending on the composition of the earth underground at the site. Air-source heat pumps are much less expensive to install, but slightly less efficient. Even so, the air-source heat pumps are much less expensive than nearly any other type of conventional heater.
Jake Marin was kind enough to supply his estimates of normal operating costs, by heating type. The table below gives the information he supplied.
|Heating type||Fuel cost||Efficiency||Cost per MMBTU|
|Air source mini-split heat pump||$0.14/kWh||3.0 COP||$14|
Jake has a few points of advice:
Even a person with a passive solar house probably needs a certain amount of heating backup for comfort, especially for inclement weather. A heat pump is a good solution for this.
Aside from passive houses, wherever a heat pump is used, it is good to have another source of heat for especially cold days, as the heat pumps loose efficiency in very cold weather and will not operate at all when the temperature falls too far. Typically the minimum temperature at which they will operate is 0º to -15º F, depending on the model and the building.
A great combination for a conventional house with good insulation and a tight shell is a heat pump with a wood stove.
In a conventional house with a standard heating system, such as oil, it is very often best to retain the old system as backup and add a heat pump as the primary heat source.
The most important thing of all is to make sure the house is properly insulated and buttoned up for air leaks. Without doing this, heating will be expensive, no matter how efficient it is.