When Phoenix residents add a heat pump to improve heating and cooling efficiency, it’s rarely a bad idea. In fact, the equipment presents a number of year-round benefits. That is, if you purchase the appropriate equipment. When you work with someone that doesn’t know how to properly size heat pumps, immediate and long-term costs are going to be a lot higher than they need to be.
Making Price Savvy HVAC Decisions.
Even though an installation with a warranty by a seasoned pro is the best way to avoid buyer’s remorse, we understand the appeal of affordable services. Not everyone has the means or desire to pay premium prices. So if you’re going to hire a cheap HVAC installer, you’ll probably want to learn a few things about adequate heat pump sizing.
At the end of the day, knowing what to look for can be invaluable. The last thing you’ll want to do is hire someone that cuts corners or lies about size requirements to make more money. While the idea to install a heat pump can be a solid one, it rarely pays off when it involves an oversized unit or incompetent service.
What is the Functionality of a Heat Pump?
In a nutshell, heat pumps are sponge-like devices that use refrigerant to absorb heat from one environment (outside or indoors) before channeling it to its counterpart. When temperatures are cold, outdoor heat is transferred inside. During the peak of the summer, heat pumps soak up replete hot air in the house and pump it out.
Both processes are not only designed for your comfort. They also work to bring room temperatures to your manual setting faster and more efficiently. In turn, you experience energy savings while taking the load off of your furnace and air conditioner. When temperatures are over 120 in Phoenix, a properly sized heat pump can pay for itself.

Where to Start When Sizing a Heat Pump.
While some homeowners simply want to improve overall HVAC efficiency, many need to properly size heat pumps for room additions or home remodeling projects. No matter your reasoning, the size of your space will help you determine the size of the unit.
However, square footage is not the most effective form of measurement. It simply gives you a good starting point. Since residential heat pump options range from 1-5 tons, the “tonnage” also needs to be evaluated. This refers to the amount of heat that a heat pump can relocate in 60 minutes time.
How Can a Homeowner Make Sense of This?
If you’ve been informed that your residence needs 2 tons of excess heat pumped every hour, then a 2-ton unit may be ideal. But this all depends on how the HVAC provider came up with their analysis. If you want to make sure you hire someone that knows how to properly size heat pumps, then there’s at least one thing they should be doing.
How to Determine Heat Pump Capacity.
Whether you care about pinpoint sizing or not, you’re going to want to have someone perform an accurate load calculation. Also known as a Manual J, gain calculation or heat loss test, it’s the only way to figure out heat pump capacity.
The complex set of calculations is used by industry professionals to measure how fast each room gains heat during the summer and loses heat in the winter. But it’s not as simple as checking some sort of temperature gauge. Nearly everything about your home is taken into consideration.

What to Look for in a Load Calculation.
The overall floor plan, room sizes and the condition of the property all impact the loss and gain of heat in a different way – not to mention the desert climate we live in. Here are some things we examine when asked to properly size heat pumps in Phoenix:
- Layout, Levels and Design.
- Material and Construction Type.
- Square Feet and Ceiling Height.
- Number and Quality of Windows.
- Insulation Type and Quality.
- Size of Attic and Crawl Spaces.
- Number of Inhabitants and Ages.
- Furniture, Decor and Flooring.
Without this type of analysis, it’s awfully difficult to perform accurate sizing.
Why Should You Properly Size Heat Pumps?
Knowing how to properly size heat pumps might not seem like a big deal, but it is. They’re designed to adequately heat and cool your home when temperatures are at their extremes. Since we experience cold weather (at night) and intense heat in Phoenix, improper sizing can quickly strain a heat pump.
An overworked unit leads to early repairs, higher energy costs and a premature replacement. Although the lifespan on a heat pump is shorter than an AC unit or furnace (because it runs year-round), it should still last you 12-14 years when sizing and maintenance are taken seriously.

Heat Pumps That Are Sized Too Small.
Undersized heat pumps are usually forced to operate at maximum capacity for long periods of time in order to satisfy set temperatures. When they’re unable to keep up with your indoor settings, they don’t stop running. As you can imagine, this wears on your system and is reflected on your electric bill.
If you made the purchase for added comfort, then an inadequate unit is not going to be much help. Unfortunately, far too many people would rather save money than properly size heat pumps. But the cost of a broken compressor is rather unsettling to say the least.
Heat Pumps That Are Sized Too Big.
Some homeowners install an oversized heat pump so they can reach optimal temperatures faster. But it’s not something we encourage. In fact, excessive capacity affects performance and lifespan in the same ways that an undersized unit does. Larger units are also more expensive.
It’s not healthy for a heat pump to frequently turn off and back on again in short spurts. This is called short cycling. Aside from increasing energy usage, it doesn’t give warmed air a chance to circulate properly. Because of indoor temperature fluctuations (cold and hot pockets in the home), humidity control also suffers.
Additional Power and Size is Counterproductive.
When duct leakage is high, heat pumps have to work harder to distribute the absorbed heat. The added capacity can be especially strenuous on the fan and other components. No matter how you look at it, expensive repairs should be expected when you don’t properly size heat pumps.

Sizing Is Meant For Heat Pump Pros.
The purchase of a new heat pump is not a decision that should be taken lightly. If you’re going to commit to a large purchase like this then it’d be wise to make sure it’s properly sized. Some contractors don’t have a problem “eyeballing things”, making a guess based on square footage, or adding a half-ton of capacity to “make sure it’s enough”.
So before you make a hire, learn what you can and be prepared to ask a lot of questions. You’ll be rewarded by better efficiency and overall savings. If you need anything else, just let us know! We’ve been helping the Phoenix community properly size heat pumps for decades now.