Sizing a New Heating System


Winter in Sacramento isn’t as harsh as it is in Denver, Chicago, or Syracuse. Of course, that’s cold comfort if it’s a freezing January night and your teeth are chattering because your old heating system isn’t up to the task. If you decide it’s time for a new heating system, you should know how to size the system correctly in order to get the proper fit (and comfort) for your home. Not sure, even after reading the tips below? Contact a heating and air contractor in Sacramento like Ace Plumbing for help!

Why Sizing Your Heating System Matters

A number of variables factor into your home heating needs. There’s the temperature you’d like your home to hold during the cold, but there are also some structural concerns to address. The latter include the age of your home, number of floors, the quality of your insulation, whether you have a basement or crawlspace, your ceiling height, and the amount of passive heat you get from sunlight through windows.

Common Sizing Methods

One of the most common methods for a layperson to size a heating unit is to figure out their home’s square footage. Once you have that, you find out your climate zone, your furnace output, and its efficiency, and you’ll know what to purchase. Right?

No. A pre-war bungalow with low ceilings isn’t going to require the same kind of output as a modern home with vaulted ceilings, good insulation, and generous southern exposure, even if they have the same square footage. Other common methods — from comparing systems with your neighbors to asking at the nearest home supply superstore — fall short for similar reasons.

Why Not Just Use Your Old Unit as a Guide?

Your old furnace isn’t necessarily a good guide for the type of unit to install next. Contractors often overcompensate on system output, meaning the unit won’t be as energy efficient as it could be. If you’ve built an addition, taken steps to upgrade your windows, roof, and insulation, or if the last contractor didn’t size the unit properly, it’s time to have your new HVAC unit sized properly!

Sizing a Heating System Correctly

The best and most reliable method for sizing is known as the Manual J Load calculation. It’s a standard established by the Air Conditioning Contractors of America (ACCA). It accounts for construction materials, insulation, room volume (not just square footage), and many other variables. It’s a bit time consuming, but the upshot is that you’ll have a unit that’s the right size for your home rather than something based on someone’s best guess. The efficiency will save you money over the long term!

Finding the Right Heating and Air Contractor

Since that isn’t exactly a job for a layperson, let’s boil it down to a takeaway that you can use: contact a professional who can accurately assess your home and your needs, and who can then suggest a new unit for your home or simply let you know if it’s time for HVAC maintenance. Ace Plumbing serves the  Sacramento area — including Folsom, Davis, and Roseville — and we’d love to hear from you. Call 916-455-4548 today!