Installing high efficiency furnace

These furnaces are designed to provide the best comfort for the least energy with the associated thermostat, controller, or application identified below, and EPA recommends that they are installed as such. That means you can keep your home warm and cozy, while still remaining energy-efficient, all winter long. Air quality. Controller: Enjoy sophisticated system management, unprecedented control and exceptional energy savings with a Comfort Sync thermostat.

The modulating multi-stage gas valves allow the furnace to operate on a quieter low-fire setting unless thermostat calls for more fire. True multi-position design allows upflow, downflow or horizontal installation with up to Controller: Designed with an intuitive interface, Wi-Fi, occupancy and built-in smarts, putting you in control of your comfort and energy savings.

The secondary heat exchanger pre-heats the incoming cool air, which significantly reduces fuel consumption. It represents the ratio of annual heat output compared to the consumed fossil fuel energy.

Note, however, that there are further loses of heat through the ductwork , especially if it is not insulated and is running through non-conditioned places such as attic and garage. These loses are not included in the AFUE value.

Did you know? An all-electric furnace does not generate flue gases and, therefore, does not have the heat loses associated with that. However, expensive electricity in most parts of the country does not make electric furnaces a feasible option for home heating.

Pro Tip: If you decided to go with an all-electric heating, consider installing a heat pump for your central system. It uses the same ductwork that your furnace would use, but produces heat using a different technology, which consumes much less energy than electric furnace.

In addition, heat pumps are reversible and, apart from heating in winter, they can also provide cooling in summer. Another parameter which allows to compare the effectiveness of the furnace is how it varies the output in response to the heating demand. There are three common types:. Once the desired temperature is reached, the thermostat signals to shut off the burner, while the blower keeps circulating the air for some time to distribute the remaining heat.

Single-stage furnaces cycle switch on and off more often than other types, since it has to start up every time the temperature drops down below the set point. The higher the number of starts and stops the furnace performs, the more wear it experiences. In addition, this leads to high fluctuations in space temperatures as the furnace will start only when it is already cold in the room and will usually heat up the space to a higher than desired temperature to keep it above the set point for a longer period.

This allows furnace to cycle less, prolonging its lifespan and providing higher levels of comfort. The operation is typically continuous long cycles , and the fuel burnt is proportional to the heat output required at any given time.

This means that the furnace uses just enough fuel to maintain comfort, resulting in higher efficiencies and elevated comfort. Variable-speed blowers are also available with each type of furnace to optimize efficiency and comfort. The speed of the blower is automatically adjusted to match the air flow with the heating demand.

For instance, the hotter the air produced by the furnace, the lower the air flow is required to heat up the space, avoiding creation of hot spots at the same time. Pro Tip: Furnace manufacturers sometimes offer two options: a constant and a variable-speed blower. It is especially beneficial to specify a variable-speed blower with single and two-stage furnaces in order to avoid discomfort associated with the cold spots at the start of each cycle.

In high-efficiency furnaces, the variable-speed blower typically comes as standard. When the time has come to replace your furnace, the question will naturally arise: which efficiency should you go for to maximize savings?

The answer to this question requires some estimations and will depend on a few factors, such as your current furnace efficiency, the size of your house, how well your house is insulated, how cold the winters are and what the fuel prices are in your area. The main criterion used for comparison is the payback period of the extra investment, or how fast the new high-efficiency furnace will repay its additional cost.

There is a steep rise in the price for the high-efficiency furnace compared to the standard-efficiency one. Pro tip: You can have a rough estimate of how much you will save when switching to a higher efficiency furnace by using online calculators such as this one. Request a more precise calculation from your HVAC engineer, who will use a specialized software, taking into account all the parameters of your house, to work out the exact saving you might get.

Chances are, you are replacing your old, inefficient furnace which has reached the end of its life and are looking to purchase a modern one. Using an online calculator and considering average gas prices in the US, the results for a sq. Considering that the lifespan of high efficiency furnace is anywhere between 15 to 30 years depending on the maintenance frequency, the return of investment of 11 years seems like a good deal.

In contrast, it will be hard to justify the extra investment for a homeowner in Seattle, where the spent money will only come back closer to the end of the furnace life. Some other factors will influence the costs and payback periods estimated above.

It uses the surrounding air - that is, the air inside your attic or crawlspace - for combustion. Assuming they're installed properly, high efficiency units work differently. They bring in combustion air from the outdoors through a dedicated pipe that's sealed off from the space that houses the furnace. Why is this such a good thing? Because in a sealed, unvented attic or crawlspace, you don't want your furnace using the surrounding air for combustion. The process standard furnaces use to produce heat is called "open combustion.

However, when it operates in a sealed environment, the volume of ambient air may not be sufficient for proper combustion; this can create a backdrafting situation where carbon monoxide CO enters your living space.

High efficiency furnaces with sealed combustion don't have this problem and are a good choice for furnaces that will operate from a sealed attic or crawlspace. If you're thinking about encapsulating your crawlspace or insulating your attic with spray foam, consider upgrading to a high efficiency furnace at the same time. The biggest drawback for high efficiency furnaces is one you may have encountered for other energy efficient devices or products: the upfront cost. Compared to a standard efficiency furnace, it's higher.

If that seems like a lot to swallow at once, remember that a high efficiency model accrues significant savings over time since it requires less energy to operate. If you're getting your first high efficiency furnace , your HVAC contractor will have to install two new components:. We've already mentioned that high efficiency units use sealed combustion, which requires a dedicated pipe for bringing in air from outside. The other special component is a PVC drain line, which may also require a condensate pump to send water from the furnace to the outdoors.

Unlike standard furnaces, high efficiency models produce condensate. These furnaces have two heat exchangers standard furnaces just have one , and the combustion gases become significantly cooler inside the second one - cool enough to form condensation. That's why drainage is required. Installing these components usually requires some light construction, which adds to the cost of installation.

The good news? It's a one-time thing. The next time you replace your furnace, the combustion air and drainage infrastructure will already be there. A furnace's AFUE only tells you what percentage of the heat produced by the unit ends up heating the home. That's useful information, but it doesn't provide the full picture on efficiency.