How do you know what the right heat pump size is for your home? Large homes and those in extreme climates need larger heat pumps, but sizing also depends on other factors, including your home’s layout, ceiling heights, and more. The size of a heat pump is measured in tons or British Thermal Units (BTUs) and shows how large a space it can comfortably cool or heat.
Size estimates can vary broadly between installers, making it important for you to work with our knowledgeable professionals at One Hour Air Conditioning & Heating in Jacksonville, Florida. We’re always on time, or you don’t pay a dime, and we also have extensive experience and knowledge about properly sizing heat pumps. Here’s some information to help you understand how to properly size a heat pump for your Jacksonville home.
Key Takeaways
- Heat pump size matters because an improperly sized model will be less efficient, work harder to keep you comfortable, and cost more money in utility bills and installation costs than a properly sized model.
- When a heat pump is too small, it will have trouble meeting your temperature demands in extreme outdoor temperatures, and a too-large model will short cycle, have higher installation costs, and be less efficient.
- Quality contractors use blower-door tests, Manual J Calculations, and Manual S calculations to determine a heat pump’s proper size and type based on multiple factors.
- The heating and cooling experts at One Hour Air Conditioning & Heating in Jacksonville have extensive experience with heat pump sizing, installation, repairs, and maintenance.
Why Does Size Matter for Heat Pumps?
A heat pump’s size is measured in tons or British Thermal Units (BTUs). BTUs indicate how much heat a heat pump removes from your indoor air each hour. When tons are compared with BTUs, one ton equals 12,000 BTUs. When sizing a heat pump, you want to match its capacity during extreme weather with your home’s largest cooling or heating load. Loads are measured in BTUs and represent how much heat your home gains or loses through its windows, walls, and leaks during the hottest or coolest outdoor temperatures you’re likely to experience.
A right-sized heat pump saves you money on your utility bills, maintenance costs, and even installation. It will be large enough to keep you comfortable regardless of the temperature outside, but not too large for your home. The right-sized heat pump will also be energy efficient and may require less maintenance.
What Happens When the Size is Wrong?
If you install a heat pump that’s the wrong size for your home, it can cause several problems. If your heat pump is too small, it won’t be able to keep up with your temperature demands in extreme temperatures. However, it’s more common for a heat pump to be too large than too small.
When you have a too-large heat pump installed, you might waste thousands of dollars on its installation costs. A too-large heat pump can also cause short cycling and stress the blower motor. This occurs when it cools or heats your home too fast, and it must turn itself off and on more frequently than it’s designed to do. This can lead to higher energy bills, reduced reliability, and increased maintenance and repair costs.
Since heat pumps are available in half-ton increments, it’s rare to find one that perfectly matches your home’s size. In its guidelines, the Air Conditioning Contractors of America (ACCA) states that it’s okay if your heat pump’s size is slightly smaller or larger than the official estimate, and it will be efficient and keep your home comfortable.
However, when a heat pump is significantly oversized, it will be inefficient and forced to work hard to keep your home’s interior comfortable. It may also cost much more to install than a properly sized heat pump.
How to Properly Size a Heat Pump
If you Google “How to size a heat pump”, you might find a lot of inaccurate information about using rule-of-thumb measurements. For example, you might be told to simply multiply your square footage by various numbers from different sources, leading to a wide range of sizes.
It’s best to avoid rule-of-thumb measurements and go with the methods our HVAC professionals use, which include a blower-door test, Manual J load calculation, and Manual S size calculation. Here’s a look at what each of these tests involves:
Blower-Door Test
When your HVAC professionals perform a blower-door test, they’ll use a large fan and a canvas to test how well your home is sealed. This test measures how much air leaks from your home by measuring the air changes per hour (ACH) or cubic feet per minute (CFM).
The measurement tells you whether it might be a good idea to invest in sealing before you install a heat pump or whether you might need ventilation. They also help your HVAC professional understand the size of the heat pump to cool and heat your home.
Manual J Load Calculation
The ACCA has issued Manual J, which quality HVAC contractors use to measure your home’s load size. This calculation helps our professionals understand your home’s heating and cooling needs based on multiple factors, including:
- Your home’s size and ceiling heights
- Your home’s layout
- Your home’s window sizes, types, and number
- Your home’s insulation quality
- Your home’s air leakage
- Local temperatures, climate, and humidity
- For ducted heat pumps, your home’s ductwork’s sizing, placement, and insulation
- Heat-generating appliances and the number of people in your home who give off body heat
- Preferred temperatures
Small differences in air leakage, windows, and insulation can translate into a difference of over a ton in your home’s load. If these factors are miscalculated, the heat pump size estimate could be significantly wrong.
Manual S Size Calculation
The ACCA also issued the Manual S size calculation to help HVAC contractors figure out a heat pump’s size and type for different homes. This standardized measurement takes the Manual J calculation and helps your contractor determine the right size and type of heat pump that matches your home’s cooling and heating needs.
The Manual S calculation is important to ensure your contractor installs a heat pump that will meet your home’s heat gains and losses year-round. If your system is too big or too small, you won’t derive the efficiency and comfort that heat pumps are known for.
Contact Our Heat Pump Experts
At One Hour Air Conditioning & Heating, our heating and cooling experts have extensive heat pump service experience for homeowners in Jacksonville. We can properly size your home and recommend the appropriate heat pump size and type.
We offer professional heat pump installation, repair, and maintenance services to keep your system functioning properly for years. We’re always on time, or you don’t pay a dime. Call us today to schedule your appointment at (904) 595-6135.
FAQs
1. Can I use simple sizing rules for a heat pump?
No. Simple sizing rules that you might find online are fairly worthless. If you use them, you’ll likely end up with a system that’s too large or too small for your home.
2. Can I size a heat pump myself?
Proper heat pump sizing requires expertise that most homeowners don’t have. It’s best to leave sizing to our experts at One Hour Air Conditioning & Heating.
3. What factors does the size of a heat pump depend on?
Proper heat pump sizing depends on numerous factors, including your home’s size and ceiling heights, layout, climate, air leakage, and more. Because of this, it’s best to work with a professional to properly size your heat pump based on industry standards.
Final Thoughts
Figuring out the right size for your new heat pump is not a simple process. Instead, it’s best to leave sizing to professionals who follow industry standards, including blower door tests, Manual J calculations, and Manual S calculations.
A properly sized heat pump will provide superior efficiency and comfort for your home year-round and help to reduce your utility costs.