Most Efficient Method of Home Heating

 colourful houses in Bo Kaap, Cape Town, South AfricaYou have probably wondered what the most efficient method of home heating for your home is. If you are building or purchasing a new home then you should definitely be concerned with this issue. Depending on what combination of methods is the most efficient will make a big difference in your monthlu bills. You should also factor in the initial cost of the systems.

Electric furnaces, gas furnaces, floor board heaters, electric heat pumps and solar heating are some of the options you have. Do you know what the best system would be for your new home?

Gas Furnaces

Natural gas and propane furnaces are some of the most popular heating choices in the mid-west. Often the same furnace will have the option to use either propane or natural gas. The energy efficiency of gas furnaces is measured by the Annual Fuel Utilization Efficiency (AFUE).

The more efficient units are the ones with the higher AFUE ratings. Most have an AFUE of between 78% and 98%. Condensing furnaces that are vented with plastic pipe have the highest ratings, typically around 95%.

Regular gas furnaces are usually on the lower end around 80%. While the condensing furnace will have a higher initial cost, it makes up for it with lower monthly fuel costs.

Electric Furnaces

Electric furnaces use electronic heating elements and a forced air fan. Due to rapidly increasing electric costs, electric furnaces are generally no longer considered to be an efficient home heating method.

However, there are exceptions to the rule. If you have access to cheap or free electricity, an electric furnace could be better for you. There are homes designed to produce low cost electric that may make it feasible to use an electric furnace.

Heat Pumps with Air Source

Electric heat pumps that use air as a source of heat can provide heat for most homes for about 50% less or better than the average electric furnace. One advantage to using heat pumps is that they are reversible.

Heat pumps can provide heat in the winter and cool air in the summer. They extract heat from the air to heat your home in the winter and they extract heat in the summer and push it out of the home causing the inside air to be cooler.

Whether being used to heat or cool your home, the principal is the same. They work by extracting the heat from the air by using a heat exchanger. The heat exchanger is a coil that is colder than the air so that the heat from the air transfers to it.

Factors that affect the cost of heating your home with an electric heat pump include the cost of electricity, the efficiency of the unit and the heat load of the home.

One problem with heat pumps is that they have to be installed according to the homes cooling requirements and the heating requirements are not fully met when they are reversed to use for heating. The balance is restored normally by using electric heating elements that are not nearly as efficient as the heat provided by the heat pump.

In order to have a unit large enough to heat your home without using the electric elements, you would have to use a unit that would be too big for air conditioning the home in the summer. A unit that large would cause the humidity of the home to reach uncomfortable levels.

However, using a proper thermostat that heats the home slowly with minimal use of the electric element’s heat, a home can be efficiently heated with a heat pump.

Heat Pumps with Groundwater Sources

There are two main types of heat pumps that use water as a source of heat instead of air. Their principal is the same as the heat pumps that use air as a source accept that the heat is extracted from water instead of air. The first type uses a renewable water source such as a well or lake. It will take water in, extract the heat from it and expel it back into the source.

The other type (Geothermal) uses a large pipe system buried under ground. The water is pumped into the unit where heat is extracted using the heat exchanger, then the water is returned out the exit pipe that loops back around to the heat exchanger after it travels a fair distance underground renewing it’s heat supply.

Of the two types of water source heat pumps, the ones with the renewable water source are usually more efficient, but they need a large enough supply of water to be effective.

A heat pump with a smaller water supply may not be as efficient as a ground loop system. So if you have access to a large body of water, we recommend the renewable source type, otherwise a ground loop system is best.

Hot Water Boilers

Hot water boilers have become fairly efficient in recent years. They require a minimum AFUE rating of 80% and many have ratings in the mid 90s. Today, slab radiation and base board radiation systems have replaced the old radiators of the past.

In a slab radiation system, high temperature plastic piping is embedded in the cement slab of the floor. When hot water is circulated through the pipes, the entire concrete slab absorbs the heat and radiates it up through the floor heating the entire room above.

One clear advantage to these types of systems is that you can adjust the heat for each room of your home by controlling the water flow to that room.

In the baseboard heating systems, pipes, with fins attached to radiate heat, are installed around the baseboards of the house. Both systems provide radiant heat that is thought to be more comfortable then forced air heat by most people.

Also, radiant heat warms the floors of the home making it feel warmer than it actually is. This allows people to keep the temperature a few degrees lower, therefore saving on heating costs.

Wood Burning Stoves

Wood burning stoves are a popular heating method in many homes. They are more cost effective especially to people that have access to free or low cost fire wood. If you live on property that has 20 or more wooded acres, you should strongly consider a wood burning stove to supplement your current heating system. Most people that use wood burning stoves have a secondary heat supply as well.

Most wood burning stoves are not capable of heating the entire house, but some can when it is not below freezing outside. If you are paying little or nothing for the wood, then they will definitely save you money in the long run.

They are not too awfully expensive to install, although some of the more extravagant models can get expensive. A reasonable price for a wood burning stove uninstalled would be just under $1,000 for an inexpensive or used stove.

Solar Heating

Solar heating is perhaps one of the most overlooked sources of heat for your home. Elaborate solar heating systems, used as the only source of heat for the home, are not usually considered a cost effective alternative unless the costs of other fuels are extremely high.

However, there are several other overlooked solar heating techniques that should be considered in addition to any other heating system you use in your home.

Homes that use solar heating techniques that supplement the current heating system are commonly referred to as passive solar homes. The basic principal of a passive solar home is to allow the sun’s heat in when it is needed, store as much of that heat as possible and keep the sun’s heat out when it isn’t needed. Here are some simple ways to maximize the use of solar heat in your home:

    1. Make it so that the majority of windows and glass on your home is on the southern facing side.
    2. Avoid east and western facing windows because they provide little sun to be permitted in the winter and allow more sun in the house during the summer when it is not wanted.
    3. Use over hangs to shade the southern facing windows and glass. The sun is low in the winter and will still shine in and the sun is high in the summer and will be shaded much of the time.
    4. Provide shade trees on the east and west sides of the home to shade the windows and keep out the sun‘s heat in the summer.
    5. Use the concept of thermal mass to hold the heat in your home in the winter. Thermal mass is anything that absorbs heat and slowly releases it. When the sun shines on thermal mass during the day, the heat is stored and released during the evening hours making the sun’s energy work long after the sun has set. Thermal mass can be any heavy substance with a surface facing the sun during the day. Examples of thermal mass could be a quarry tile floor over a concrete slab or thick plaster walls that the sun hits during the day.

Summary

Okay, we have covered the most efficient methods of heating your home. Which method is best for you will depend on several factors such as: are you building a home or trying to make an existing house more efficient, energy costs in your area, how much you have to invest in the initial installation of the heating system and many other factors that will be evident to your situation.

Overall, in a general sense, judging by the information presented in this article, it would seem that the most efficient home heating system would be a combination system of an electric heat pump with a renewable water supply combined with sensible solar heating techniques and perhaps a wood burning stove if you have access to the wood.

You may also want to consider the use of wood pellets if you do not have an endless supply of firewood. Often, if you do not have special access to another cheap source of energy, a gas furnace is the most efficient method for you.

Photo by Paul Mannix, Creative Commons Attribution License