An energy saving furnace can be one of the best investments you can make in terms of cutting your carbon footprint, reducing your home energy bills, and saving money.
Most older furnaces are low- or mid-efficiency furnaces. Low-efficiency furnaces have an Annual Fuel Utilization Efficiency, or AFUE, of 79% or lower (with models older than 20 years likely considerably lower), which means they convert 79% or less of the energy in the fuel they consume, into heat that actually heats your home (the rest goes out the chimney or exhaust pipe. Mid-efficiency furnaces have an AFUE of 80 to 83%, while high efficiency furnaces are generally from 90 to 97% efficient. There is a gap between mid-efficiency and high-efficiency furnaces because the technology changes from mid- to high-efficiency, from a standard to a condensing furnace (where the water vapor is condensed out of the exhaust to recapture the heat in it).
If you are looking for a new furnace, make sure to figure out the total cost of ownership over the life of the unit (typically 20 years or more). You will spend a fair bit more up front for a high efficiency model, but you will save a lot of money on annual heating costs, especially as natural gas prices are likely to climb much higher in coming years, compared to their fairly stagnant price through the 90's and much of the first decade of this century.
For example, when I bought my 94% efficient furnace in 1998, I paid ,800, while an 80% efficient model would have cost just ,500. Why spend the extra ,300 for an extra 14% efficiency? There are three main reasons.
1. Cutting your CO2 emissions: if you are concerned about the problem of climate change - as everyone should be - buying the most energy efficient furnace you can get will cut your CO2 emissions considerably.
2. Saving on fuel costs: natural gas prices have been stable for years, but a number of factors are contributing to increased scarcity of natural gas, including massive consumption of natural gas for the Alberta tar sands project, increased use of natural gas by industry, and increased reliance on natural gas for peak load electrical generation by utilities.
3. Saving on electricity costs: a typical high efficiency furnace uses about one fifth as much electricity as a mid- or low-efficiency model.
In addition, depending on where you live, you may qualify for government tax credits or energy efficiency rebates when you install an ENERGY STAR or high efficiency model.
An energy saving furnace doesn't vent up your chimney. High efficiency furnaces extract so much of the heat out of the exhaust gases, that they vent out the side of your house through PVC tubing; you can feel the exhaust air coming out and it's hot, but not hot enough to burn. High efficiency furnaces also have an air intake tube, which is key to their efficiency: they do not draw interior air into the sealed combustion chamber, which prevents the furnace from sucking cold air into the house through drafts such as cracked window panes or poorly sealed doors.
If you're considering buying an energy saving furnace I would recommend starting with a list of the most efficient furnaces in the BTU category you need. Brands such as York, Carrier, Bryant (made by Carrier) and Air-Ease have some very high efficiency models. For a full list, visit the ENERGY STAR website, and check in their heating and cooling section for a complete list of ENERGY STAR qualified furnaces.
One thing to note is that the brand of the furnace you buy matters less than the manufacturer. Some brands, such as Frigidaire, Kenmore, and Maytag, do not make furnaces themselves, instead they repackage furnaces made by actual furnace manufacturers. What sets a Maytag model apart from the exact same furnace branded by someone else? Nothing, in terms of quality. The only difference is in how easy it is for salespeople to market the product, since people place unwarranted faith in a brand name. If the warranty is the same and the product is the same, pay no attention to the brand name. You can usually tell when two brands are both the same furnace when the efficiency, BTU capacity, and model number are all the same or the model number differs only by a letter or two.
There are definitely some brands that have built a solid reputation for reliability, but studies suggest that in over 80% of cases where unscheduled maintenance is required on a furnace or air conditioning system, at least part of the problem originated with a faulty installation, rather than with the quality of the brand purchased. That's why it's crucial to find a top-notch HVAC contractor.
Look for an HVAC company with a solid reputation, who has installed the furnace you're considering buying many times. Going for a bigger operation - at least a dozen employees - is usually a good bet, as companies don't get that big by running a shoddy operation. Look for awards or customer reviews or customer references, and make sure you have a professional, courteous, and trustworthy salesperson. Invite them into your home to do an assessment, and check that they understand your concerns with energy efficiency, understand the relative efficiency of different models and brands, and do not slam the competition. If a salesperson tries to convince you that energy efficiency shouldn't be a major consideration, or they don't understand the issues or the math, find another company.
Also be wary of someone who focuses on low price. You want quality and you need to be willing to pay for it. Ensure warranty and service information is agreed on from the outset; you need at least a one-year warranty and there should be the option to pay for an annual service contract; find out the cost per year (for current customers) for each of the first, fifth, tenth, and twentieth years (as service prices rise as the equipment ages).
Your contractor should be willing to remove all equipment that is no longer needed, and dispose of it at no extra cost to you, and at the time of installation. You don't want to be left with that mess.
Don't forget to ask friends and neighbors for references, since companies. Companies that grow their business through referrals are obviously doing quality work. Those that grow their business through big advertising budgets may not be.
You should ask your HVAC salesperson to size the equipment you'll need. Typical BTU ratings for home use are 40,000 BTU for smaller homes or warmer climates, to 120,000 BTU for a large home in a cold climate. A competent HVAC contractor will do a load calculation for your home based on interior area, insulation levels in walls and attic, and the local climate. Some contractors will just do a ballpark estimate in their heads - which may be fine if they're very experienced. Others may do the work on paper or with specialized software. It's important that you trust what they've come up with. For instance, most of the contractors I interviewed wanted to give me a 60,000 BTU furnace for my 1,300 square foot home. But the one I eventually chose told me to go with their 40,000 BTU high efficiency unit, because it was 2% more efficient than their ultra high efficiency 60,000 BTU model and because they said there would be very few times when I'd need the full 60,000 BTU - namely extremely cold nights, of which we only get two or three a year. Contractors don't want to be accused of underestimating the required capacity, so they may overestimate to avoid complaints when you're freezing during a cold snap. In our case, the lower capacity furnace has never had trouble keeping us warm on even the coldest nights.
If you're going to the expense of installing an energy saving furnace, make sure the installation comes with a programmable thermostat. Many high efficiency furnaces require a specialized thermostat that comes as part of the installation. If yours doesn't, get a standard programmable thermostat installed as part of the deal; it should support at least four different temperature settings for each day of the week. Using a programmable thermostat can further increase the savings you derive from an energy efficient furnace - it can make a difference of up to 10% on your fuel costs.
You can buy inexpensive disposable furnace filters at most building supply stores. Such filters typically need to be replaced once a month, more often if you have dust or pet hair problems. A more convenient choice is a whole house pleated filter that consists of fanfold filter paper enclosed in a large boxlike structure; while it costs quite a bit more, it only needs to be changed once a year and filters out much finer particles. Whole house filters also provide less air resistance to the furnace fan, making it more efficient.
You should also have a humidifier installed as part of your new furnace. Adding humidity to the hot air coming from your furnace improves comfort, making the indoor air feel warmer (that's why in cities like Toronto we have a Humidex advisory -- the added humidity makes hot air feel even hotter). A humidifier in your furnace will not only improve comfort, but reduce the chance of your getting colds, as you won't have your lungs and airways dried out by the heated air.
An energy saving furnace should allow you to enjoy comfortable temperatures without your spending a fortune on natural gas. By choosing a high efficiency model, a competent HVAC contractor, and the right filtering, thermostat, and humidifier options, you'll experience quiet comfort at a lower cost, while cutting greenhouse gas emissions as well.
