Thursday, July 2, 2015
A custom home may depend on solar, geothermal or wood stoves for its heat, but the building code, loans and future resale values require that the house be equipped with an adequate conventional heating system. There are many deciding factors in what type of system to chose. The type of heating system chosen is determined by the budget, personal preference, location and resources available.
The required energy may be supplied by natural gas, propane or electricity. All types of systems actually require some low level of electricity to power fans, pumps and controls. The actual utility chosen to heat the home may be determined by location. All sites should have electricity, but whether your site has natural gas or must be supplied with propane should be determined.
These days, electricity is seldom the first choice. Electric heat usually results in a higher utility bill. Electric heat can result in a lower upfront or capital cost, Electric heat can be the least expensive way to install heat in a home, but seldom will be the least expensive to operate. Note that an electric outlet cannot be placed above an electric baseboard heater. Electric heat might still be chosen if most required heat is to be supplied by wood or solar.
Propane is often chosen on rural sites. It is a gas when it enters the home. It is delivered by truck to a tank near the home. The tank can be leased or purchased. The tank can be buried (this requires the tank be purchased) or placed on grade and even hidden with landscaping. The energy delivered by propane is slightly less than the energy delivered by natural gas. A professional may need to adjust the orifice sizes on old appliances. Propane does allow for gas cook tops, clothes dryers and fireplaces. Propane cannot be used in a basement mechanical room without complicated detectors. A propane fueled mechanical room must be in a true walkout or upper floor. It cannot be in a basement or even a garden level. Propane is heavier than air. It settles and pools if there is a leak. Leaking propane would be vented by opening doors.
Natural gas is usually chosen if it is available. If a site is supplied with natural gas or it's nearby, gas will be run into the house. Natural gas will result in a lower utility bill than propane, with electricity being higher still. Natural gas and electricity will result in monthly bills. Propane is billed upon delivery, resulting in irregular and large bills. Natural gas is lighter than air. Leaking natural gas could be vented through open doors and windows. Again, natural gas allows for gas cook tops, clothes dryers and fireplaces.
Another decision to be made is whether to heat with hot water or forced air. Both choices have advantages and disadvantages, and both can be run off natural gas, propane or electricity. Budget, personal preferences and practical considerations affect the choice. This should be discussed with the architect.
A hot water heating system can be "In Floor Radiant Heat", "Underfloor Radiant Heat" or baseboard hot water heat. Hot water heat comes off a boiler. Any type of hot water heat usually costs more than forced air. Any type of hot water heat can be broken into multiple zones, each zone with its own thermostat. Adding air conditioning is awkward as there is no duct system.
"In Floor Radiant Heat" runs heating tubes through a 1 1/2" thick, light weight concrete floor. This adds weight to the structure, but is easily dealt with. The cost of concrete and supporting it can make this the most expensive commonly used heating system in residential projects. The height added by the concrete must be considered in the framing. Wood flooring requires 2x4 furring. "In Floor Radiant Heat" gives a warm floor, no moving air and spaces clear of heating registers or baseboards.
"Underfloor Radiant Heat" tubes are stapled under the sub-floor with insulation below that. It eliminates the concrete floor. Construction details must be considered. The nails from installing a wood floor will pierce the sub-floor, but cannot pierce the heating tubes. The final results are very similar to those in a home using "In Floor Radiant Heat".
Hot water baseboard heat is an older, less expensive way to heat with water. There can still be multiple heating zones. Baseboards run along outside walls and anywhere heat is needed. Nowadays, the baseboard radiator sits where the base trim would be. A typical baseboard radiator is about 2" deep and 8" high.
All hot water heating systems result in a quiet home with no moving air. However, any kind of hot water heat means that air conditioning must be a separate system with its own ducts and delivery system. Adding air conditioning to a house using hot water heat again increases the budget.
A forced air heating system requires a furnace, supply ducts and a return air system. A forced air heating system is more difficult to break into zones. It does easily lend itself to adding air conditioning. A humidifier can also be easily added. Forced air heat will usually be less expensive than hot water heat. It has a quicker response time making it a better choice in vacation and second homes. If you arrive at a vacation home late in the day, the house will be cool from having a lower thermostat setting while the house was unoccupied. Forced air heat will respond more quickly than hot water heat.
Choosing which method for heating a home is a major choice. It can affect the structure of the home and its basic layout. Running ducts from a mechanical room requires some planning. Hot water heating tubes can usually be run anywhere. Propane can affect the basic layout of the house. A tight budget, being a vacation home or the desire for air conditioning can make a forced air heating system an appropriate choice. A home with a quiet heating system, no registers and a warm floor attracts many home owners. Discuss these options with your architect and consider all possibilities.