HEATING WITH GAS
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If your present home-heating system is costing too much to operate or is in poor condition or if you are planning on buying a new home, you are probably considering your heating options. About 60 percent of the energy required to run the average home is used for space heating. Therefore, one of the most important projects you will undertake as a homeowner, along with insulating and air sealing, is choosing, changing or upgrading your heating system. A smart decision about heating can significantly reduce the cost of running your home and also make your home more comfortable. Some impressive improvements have been made in heating systems in recent years, and there is a wide range of good equipment on the market.
You will be using your new or improved heating system for a long time, so it is important to do your homework before you make a choice. It is worth taking the time now to ensure that you make the best choice for your situation. You should thoroughly investigate all your options first. These days, however, your options may be quite bewildering because of the wide range of equipment and energy sources available. This booklet will help you make the right buying decision. You will find it useful whether you are installing a system in a new home, replacing a system in an existing home or simply upgrading your present system.
Before proceeding any further, you should familiarize yourself with a number of basic concepts that will help you understand your options.
All fuel-burning systems (natural gas, oil, propane, wood) lose heat because of transient operation, cold start-up, incomplete combustion, heat carried away in combustion gases and warm house air drawn up the chimney. The extent of these losses determines the efficiency of the furnace or boiler, given as a percentage indicating the amount of original heat that actually warms the house.
Steady-state efficiency measures the maximum efficiency the furnace achieves after it has been running long enough to reach its peak-level operating temperature. This is an important standardized testing procedure that is used by a serviceperson to adjust the furnace, but the figure it gives is not the efficiency the furnace or boiler will achieve in actual use over the course of a heating season. This is much like the difference between the fuel consumption figures published for cars and the actual consumption of the car in day-to-day service.
Seasonal efficiency takes into consideration not only normal operating losses, but also the fact that most furnaces rarely run long enough to reach their steady-state efficiency temperature, particularly during milder weather at the beginning and end of the heating season. This figure, better known as the Annual Fuel Utilization Efficiency (AFUE), is useful to homeowners because it provides a good indication of how much annual heating costs will be reduced by improving existing equipment or by replacing it with a higher-efficiency unit (see Table 3, "Typical Heating System Efficiencies and Energy Savings," on page 52).
If you are heating with natural gas or propane or you are considering one or the other, the more you understand the terminology associated with gas heating systems, the better equipped you will be to make a wise heating system choice. The text box "Gas Heating Terms" presents some of the basics.
Gas Heating Terms
The heating capacity of appliances may be expressed in kilowatts (kW), British thermal units per hour (Btu/h) or megajoules per hour (MJ/h).
1 kW = 3414 Btu/h = 3.6 MJ/h
Energy consumption may be measured in kilowatt hours (kWh), British thermal units (Btu) or megajoules (MJ).
1 kWh = 3414 Btu = 3.6 MJ
The gas industry still commonly uses Btu/h for rating heating appliances, but newer equipment should also be labelled with the equivalent rating in kW. The heating capacity of electric heating systems is usually expressed in kW. Most home heating appliances have capacities between 40 000 and 150 000 Btu/h (about 12 kW to 44 kW).
Consumption of natural gas is measured in cubic metres (m3) or cubic feet (cu. ft.). This is the amount that your gas meter registers and the amount that the gas utility records when a reading is taken. The unit of measurement used in billing is inconsistent across Canada. If your utility bills you in units different from those on your meter, use one of the following conversions:
- to convert cubic metres to cubic feet, multiply by 35.3
- to convert cubic feet to cubic metres, multiply by 0.028
One cubic metre of natural gas contains 37.5 MJ (35 500 Btu) of energy.
Consumption of propane is usually measured in litres (L), with propane having an energy content of about 25.3 MJ/L.
In general, the same technologies and comments apply to propane as to natural gas, with slight differences in efficiencies. Propane has a lower hydrogen level than natural gas. About 3 percent less energy is tied up in the form of latent heat with propane systems than with natural gas. This means that conventional and mid-efficiency propane furnaces can be expected to be slightly more efficient than comparable natural gas units. On the other hand, propane's lower hydrogen content makes it more difficult to condense the combustion products, so that a propane-fired condensing furnace will be less efficient than the same unit fired with natural gas.
Certification and standards
All gas-fired appliances sold in Canada are required to conform to safety standards established by the Canadian Standards Association (CSA). As proof of compliance, they are also required to be certified by an independent body accredited by the Standards Council of Canada, such as CSA International, Underwriters Laboratories Inc. (UL), Underwriters' Laboratories of Canada (ULC), Intertek Testing Services NA Ltd., or OMNI-Test Laboratories Inc. Before purchasing your heating equipment, be sure it carries a certification label from one of these agencies.
The CSA standards for gas-fired furnaces and boilers also require compliance with the efficiency levels currently prescribed in the federal Energy Efficiency Regulations. (See "Energy Efficiency Standards" on page 15 for more information.)
The efficiency of your heating system can be improved in many ways. Some improvements are simple enough that you may be able to do them yourself. Others require changes that can be performed only by a licensed service-person, a qualified heating contractor or, in the case of electric systems, an electrician. All improvements should pay for themselves within a reasonable time. When you are thinking about your heating system, remember to also consider your water heater.
Source: Natural Resources Canada (NRCan) - Office of Energy Efficiency
The Heating and Cooling Series is published by EnerGuide, an energy efficiency labelling initiative of Natural Resources Canada's Office of Energy Efficiency. EnerGuide is the official Government of Canada mark associated with the labelling and rating of the energy consumption or energy efficiency of household appliances, heating and ventilation equipment, air conditioners, houses and vehicles.
EnerGuide also helps manufacturers and dealers promote energy-efficient equipment and provides consumers with the information they need to choose energy-efficient residential equipment.