We humans are very sensitive to temperature changes. The average homeowner can detect a temperature fluctuation of just two degrees from room to room. Given this sensitivity, it's no wonder many homeowners say that inconsistent temperature between rooms, levels or times of day is their biggest complaint.

Homeowners are also financially sensitive; after all, who wants high utility bills?
Installing a multi-stage heating and cooling system is the best practice to keep you comfy in both body and pocketbook.

While a single-stage or conventional heating system puts out a fixed amount of heat per hour and is either on or off, a multi-stage furnace produces heat at two or more rates. This allows the system to deliver a lower volume of conditioned air over a longer period of time, resulting in more consistent room temperatures.

Multi-stage heating systems also operate at a higher level of efficiency. The concept is similar to driving a car. Stop-and-go traffic will drive your fuel efficiency down, while “highway” miles, or maintaining a consistent speed over longer periods of time, reduce fuel usage. By operating at only 60% of the systems total capacity, less fuel or electricity is required by the system to maintain a constant temperature.

Unless you've done previous HVAC work, a multi-stage heating system will have to be installed by a qualified HVAC contractor. During installation, there are several important tasks for you to both manage and perform.

Here's what to watch for:

Review HVAC drawings prior to construction to ensure you know where the diffusers are located. This will come in handy when it's time to move in furniture and install window treatments, which shouldn't block diffusers.

Consult with the HVAC contractor on specific system sizing. Ask whether the system was sized according to industry standards, like the Air Conditioning Contractors of America's Manual J

Make sure the thermostats in the home are compatible with a multi-stage heating system.

Have your HVAC contractor teach you how to operate and maintain the system after installation, to help ensure a long life.

Why size matters

Determining the proper size for the heating system requires estimating heat loss through the roof, walls, windows, basement, and other home components under severe outside conditions. The size of the HVAC system is also relative to other improvements to the home, like air tightness and better windows. To properly size heating and cooling equipment, HVAC contractors should perform an engineered analysis according to industry standards, like the
Air Conditioning Contractors of America's Manual J.

Installing oversized heating and cooling equipment is, unfortunately, very common and can lead to high energy bills and uncomfortable conditions for the homeowner. Air conditioning units that can "deep freeze" a room in minutes are especially problematic because they operate for short periods of time, and only a few times a day. This reduces their ability to remove moisture from the air and rooms become humid or damp feeling.

Yuck.

Because a multi-stage system delivers a lower volume of air, special care must be taken when choosing diffuser outlets. Oversized outlets won't properly mix the conditioned air with air in the room, and defeat the purpose of a multi-stage heating system.
The Department of Energy has some great information about how to choose the right heating system for your home: visit the Implementation Tools section of www.energycodes.gov.