s architects, our clients are always asking for guidance on what type of heating or cooling system will be best for their home. The answer is not a simple one, and making a decision usually involves weighing a combination of personal preference, initial vs. life cycle costs, practical constraints, and climate considerations. There are a lot of residential heating options out there, and deciding which one is appropriate for your situation will not only impact your future utility costs, but also your level of comfort and satisfaction with your home.
Some of the practical considerations that weigh in on the decision are:
1. Climate
- If you live in a hot climate, cooling will be the primary consideration. Heating will be a secondary concern and may only be required very occasionally.
- In most areas of the country, both heating and cooling are required, depending on the season. Choosing a system that does both efficiently is important
- Some mountain environments don’t require cooling, or natural ventilation can be used to control the comfort level and mechanical air conditioning is not necessary.
2. Availability of energy sources
- Depending on location, electricity, natural gas, or other public utilities may be unavailable or prohibitively expensive.
- Renewable energy sources may be available and cost effective to utilize (solar in the Southwest, wind on the coast, geothermal near a large water body)
3. Relative cost of energy
- Electricity rates vary significantly
- Natural gas is typically a good value, but not always available
- Heating oil and Propane are usually delivered by truck to your site. They may or may not be less than electricity, but delivery can be subject to weather and seasonal accessibility challenges.
4. Initial costs vs. life cycle costs are always a consideration. In general, the systems that cost the most to operate are the least expensive to purchase and install. A system that uses very little or no energy may be expensive to buy, but might pay for itself in a reasonable time and end up saving money in the long term. Energy efficiencies of the different systems vary greatly.
5. Personal preferences vary
- Some people find moving air (especially cool air from air conditioning) to be uncomfortable.
- Individuals with allergies or respiratory ailments may be affected by forced air systems, which tend to re-circulate dust and other airborne contaminants.
- Some systems are better for zoned comfort, allowing inhabitants to vary temperatures in different areas of the home.
6. Space requirements may be an issue
- Duct systems may need dropped ceilings, soffits, and vertical chases
- A/C condenser units need to be outside and near mechanical room
- Hydronic systems work best in concrete floors or with a gypcrete overlay
- Baseboard heaters take up floor space and affect furniture layouts
Here is an overview of the commonly utilized systems and their pros & cons:
Electric resistance heat
(baseboard, fan forced wall heaters, forced air)
Pros-
- Inexpensive upfront cost
- Easy to control heat levels in individual rooms
- Doesn’t require gas service
- Can be turned down during the day to save energy
Cons-
- Inefficient and expensive to operate
- Requires a separate system if A/C is desired
- Dry heat, requires humidification in most climates
- Most systems don’t utilize outside air, so a separate air exchange system is required
- No heat during power outages
Best use-
Not recommended unless gas service is unavailable and low cost is top priority.
Electric heat pump:
(forced air system with heat exchanger, basically an A/C system run in reverse)
Pros-
- Doesn’t require gas service
- High efficiency
- Fast response – changes the ambient air temperature quickly
- Can be turned down during the day to save energy
- Moderate initial cost
- Can be retrofit to existing forced air system
- Works equally well for heat & A/C
Cons-
- Requires a condenser unit for each zone
- No heat or cooling during power outages
- Requires a duct system
- Re-circulates inside air
Best Use-
Where gas is unavailable or expensive. Heat pumps are best used where heat as well as A/C are necessary.
Gas fired forced air:
(conventional furnace, with or without A/C)
Pros-
- Natural gas is usually inexpensive relative to other sources
- Can be high efficiency depending on equipment and design
- Moderate initial cost
- Fast response – changes the ambient air temperature quickly
- Can be turned down during the day to save energy
- A/C function is optional, and can be upgraded for minimal cost
- Popular system, so repairs are usually fairly easy and inexpensive
Cons –
- Gas availability varies
- If required, propane and heating oil are expensive and require a tank
- Requires a duct system
- Re-circulates inside air
- Gas leak and Carbon Monoxide hazards exist
- No heat or cooling during power outages
Best Use-
When natural gas is available and inexpensive, space required for ducts is not an issue, and initial cost is a primary consideration.
Hydronic radiant floor heating:
(heated liquid circulated through a network of concealed piping)
Pros –
- Heats objects rather than the air, so it is more comfortable heat.
- No re-circulated air, so indoor air quality is better
- No visible appliances or registers
- No sensation of moving air
- Floor, furniture and other objects are always warm / cool
- Boiler can be used for domestic water heating as well
- In rare cases, wood can be a fuel source rather than gas
Cons –
- Higher initial cost, moderate operating cost
- Slow response time – can take several days to change the temperature significantly
- Can’t be turned down for short time periods
- Cooling function doesn’t work as well as forced air – condensation can be an issue
- Retrofitting, modifying or expanding system can be difficult
- Needs concrete, gypcrete, or other thermal mass to work well
- Requires ventilation system to exchange air
Best Use-
When the highest level of thermal comfort is desired. Ideal system when heating is the primary function, cooling is secondary, and short term temperature fluctuation is not required.
Electric Radiant Heat:
(Similar to hydronic, except for the following)
Pros –
- Less expensive initial cost
- Works best with thermal mass, but can be used without
- Can be used for small areas to supplement other systems
- Can be supplemented by solar photovoltaic panels
Cons –
- Expensive to operate
- No cooling function
Best Use-
When the comfort of radiant heat is desired, and gas is unavailable or expensive. Electric radiant is popular for small areas (bathrooms, kitchens, mudrooms) in homes that have non radiant systems.
Pros-
- Add to the ambiance of a space
- Wood heat feels good, similar to radiant
- Fireplaces and stoves can be gas or wood burning
- Visual as well as functional benefit
- Provide heat during power outages
Cons-
- Fireplaces and stoves take up floor space
- Firewood requires storage space and can be messy
- Wood burning appliances require cleaning and maintenance
- Potential fire hazard
- Aren’t effective at circulating heat to large spaces
Best Use-
Fireplaces and woodstoves are great at supplying supplemental heat, but are not always feasible as a primary heat source. They are common in mountain homes, and can be a huge asset during prolonged power outages.
Some alternative energy sources can be used with heating and cooling systems to cut operating costs and environmental impacts. Some of the options that are available include:Solar hot water – Solar Panels (usually roof mounted) can supply heated water to hydronic systems. Limited to cooler climates that have predominately clear skies.
Solar Photovoltaic – Solar cells in a variety of forms generate electricity that can be used to supply electric heat pumps, radiant or resistance heating systems.
Geothermal – Captures heat from the earth or large water bodies to supply hydronic systems or electric heat pumps. Despite what common sense would imply, heat can be extracted from earth or water that is at relatively low temperatures (32-55 deg Fahrenheit) and used to heat water or air to temperatures in the human comfort range.
Wind or moving water can turn generators that produce electricity. These systems are less common, but if the environment you live in has one of these energy sources, it can be utilized to heat and cool a home.
Upfront costs for alternative energy systems tends to be higher than for conventional public utility powered systems, but the energy savings can be substantial. It is worth considering the cost and environmental benefits that alternative energy systems can provide when making the decision of which type of climate control system to use in your home.
We have seen many of these systems installed in the mountain homes we design, and can help you make informed decisions on which system will be best for your project. We try to stay informed of the best technologies because we know how important the climate control system is to the proper function and overall enjoyment of a quality home.
Tom Russell, LEED AP and John Hendricks, AIA Architect
Hendricks Architecture, mountain architects in Sandpoint, Idaho.
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