When they’re done right, HVAC zones can seriously improve indoor comfort. Zones provide more control over the temperatures in different parts of your home, so you can dial in the perfect temperatures anywhere, anytime.
If you’re not familiar with zoning, it’s when you partition different areas of your house for heating and air conditioning. A common setup in two-story homes is to have two zones: one for upstairs and one for downstairs. Only need to heat your upstairs bedrooms at night? Set the thermostat to 67 for your upstairs zone and 62 for the downstairs. Then you can reverse the two the next morning.
Of course, you can have as many zones as you want to depend on your home’s floor plan and size. The benefits of a proper zoning setup include:
- More control over indoor comfort
- Even temperatures throughout your home
- Lower energy costs
Those are all good things! Unfortunately, there’s a catch.
Many zoned systems have major problems
Zoning an existing HVAC system isn’t always straightforward. In the absence of key modifications, splitting your system into zones can easily create problems that negate the benefits of zoning.
And even if you’re willing to get new HVAC equipment that accommodates different zones, you have to be sure you’re getting the right type.
Ok, so what does a dual fuel HVAC system have to do with zoning?
Before we answer that question, it helps to understand the problems with many zoning setups. We encounter lots of poorly designed zoning arrangements in residential HVAC systems throughout the Atlanta area, most of which have these attributes:
- The HVAC system is the right size for the whole house, but it’s way too big for just a section of the house (a single zone).
- To address that problem, the installers put in a bypass duct. Instead of trying to push a huge amount of air into a single zone — a scenario that leads to excess static pressure and overworks the system — a lot of conditioned air gets dumped back into the return side of the system.
This setup gets you the zones you want, but there are costs.
In summer, the system sends a lot of cold air back into the air conditioner, which increases your risk of freezing the coil. In winter, the excess heat ends up radiating back into your house anyway, negating a lot of the benefits of having zones. You also lose out on energy efficiency improvements since the system runs at full capacity even when you only need it to heat or cool one section of your house.
The solution to this problem — and we wrote a whole article about this! — is to always use variable speed HVAC equipment for zoned systems.
And if you get a dual fuel variable speed system, that’s even better.