The Ultimate Guide to Heat Pump Sizing

Heat Pumps, HVAC

Posted by Brad | March 5, 2024 | Reading Time:

Heat Pumps are all the rage right now, but in order to effectively harness their numerous benefits, they need to be properly sized for your home. That’s why we’ve created The Ultimate Guide to Heat Pump Sizing. This guide aims to provide homeowners with the knowledge needed to select the right heat pump size for any application, ensuring optimal comfort, efficiency, and long-term savings. At Cross Heating & Air Conditioning we pride ourselves on being your go-to source for all things Heat Pumps. From install, to maintenance, to repair, our friendly and knowledgeable technicians have seen it all, and are here to answer any questions you may have. We’ve been around the block a time or two, when it comes to Heat Pumps (since 1990, but more on that later). So you can be sure we have the know-how to help get you the best fit for efficient home comfort for years to come. Let’s dive in!

Understanding Your Heat Pump

Before we look at how to size your unit, it’s important that you’re familiar with how a properly sized heat pump works. Ultimately, heat pumps operate by transferring heat from one source to another. In winter, it extracts heat from the outside air (or ground) and transfers it inside. In summer, it reverses the process, removing heat from your home and releasing it outside. In heating mode, refrigerant passes through the outdoor unit's evaporator coils. Despite cold outdoor temperatures, the refrigerant can absorb heat from the air. The refrigerant, now a warm vapor, is compressed by the compressor, which increases its temperature further. The vapor passes through the indoor unit's condenser coils, releasing its heat into the indoor air. In cooling mode, the process is reversed. It’s also important to note that heat pumps come in a variety of different types, which include air-source, ground-source, mini-split (ductless), dual fuel heat pumps, but general sizing rules apply to all of them.

The Importance of Proper Heat Pump Sizing

Selecting the correct size for your heat pump is important for many reasons:


An appropriately sized heat pump operates more efficiently, saving energy and reducing your utility bills.


Correct sizing ensures consistent and effective temperature control, enhancing indoor comfort.


Oversized or undersized units can lead to short cycling or continuous operation, respectively, causing premature wear and tear, and unexpected repair costs.


Proper sizing avoids the unnecessary expense of purchasing a unit larger than needed or incurring higher operational costs with an undersized unit.

Factors That Influence Heat Pump Sizing

Here are the 5 key factors should be considered when sizing a heat pump:


The local climate significantly impacts the heating and cooling loads of a home. Regions with extreme temperatures require heat pumps with higher capacities. Here in Ontario we can be subject to some pretty harsh winters, so keep this in mind when choosing your heat pump!

Home Size and Layout

Larger homes or those with multiple levels typically need larger heat pumps. The layout also affects airflow and temperature distribution.

Insulation and Air Sealing

Well-insulated homes retain heat more effectively, potentially reducing the size of the heat pump required. It’s good practice to inspect the insulation around doors, windows, attic and around your ductwork prior to installing a new heat pump.

Windows and Doors

The quantity, quality, and orientation of windows and doors influence heat loss and gain, affecting the heat pump's sizing.

Occupancy and Lifestyle

The number of people in your home, estimated usage, and personal comfort preferences can alter the heating and cooling demands of a home.

The Heat Pump Sizing Process

When you call Cross Heating & Air Conditioning for your heat pump installation, we will:

Calculate the Heating and Cooling Loads

This involves determining the amount of heat energy needed to maintain a comfortable indoor temperature year-round. Our technicians use industry standard calculation methods to assess your heating and cooling requirements accurately.

Consider the Unit's Efficiency Ratings

Heat pumps are rated by SEER (Seasonal Energy Efficiency Ratio) for cooling efficiency and HSPF (Heating Seasonal Performance Factor) for heating efficiency. Higher ratings indicate more efficient units that can provide the same comfort with less energy, potentially allowing for a smaller size and bigger savings!

Select the Correct Size

Using the load calculations and efficiency ratings, we’ll recommend a heat pump with the capacity that matches your home's needs.

Professional Installation Is Key

In addition to being sized properly, a heat pump's performance heavily depends on proper installation. That’s why you can trust the team at Cross Heating & Air Conditioning! We were ahead of the curve when it came to heat pumps, installing our first one back in 1990! And we know that factors like ductwork condition, refrigerant charge, and unit placement play significant roles in your system's efficiency and longevity. We’re proud to be the only contractor in Canada who assisted Natural Resources Canada (NRCAN) with developing an air source heat pump sizing and selection guide. In addition, our team was invited to be a guest speaker about air source heat pumps at the University of Waterloo's Net Zero Conference last spring. So you can be sure we know our stuff!

Cross Advantage Program

Once installed, one of the most effective ways to maintain your heat pump is by signing up for our exclusive Cross Advantage Program. For just $18.95/month you’ll get the peace of mind of pre-scheduled, semi-annual heat pump maintenance. You’ll also get:
  • 1-year repair warranty
  • Annual HVAC Dollars
  • 10% discount on future repairs
  • 20% discount on air filters
  • Reduced service rates
  • Product warranty protection.
Give us a call today to learn more or to sign up for the Cross Advantage Program! In order to get the most out of your heat pump it’s important to be proactive about your maintenance with a professional service call. Regular maintenance will keep your home safe and comfortable for years to come!

The Equipment You Need at a Price You Can Afford

Keeping your home’s comfort systems running safely is something we all deserve. That’s why we’re proud to help homeowners improve their quality of life at home, no matter your current situation, with our industry-leading financing options. We’ve partnered with FinanceIt to offer you:
  • Simple, easy online applications
  • Instant Pre-Approval
  • $0 Down Payment
  • Pay off your loan on your schedule, penalty-free
Contact us today to learn more about how our financing options can help you get a new heat pump installed faster than you thought possible! Sizing a heat pump correctly is a complex process, but by understanding these aspects and following our approach to sizing, you can rest assured that your new heat pump will provide efficient, effective, and reliable heating and cooling for years to come. Contact us today to schedule your heat pump installation service!
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