A Guide to Residential HVAC System Sizing

Installing a new HVAC system in your home requires a lot of planning, and sizing is one of the essential elements. If your AC unit is too small, it won't function properly or keep your home at the right temperature. Additionally, a large HVAC system can lead to moisture buildup in your Northern California home. You also have to consider how much power you need for central air systems. Installing the wrong size equipment may increase energy costs because it runs inefficiently and keeps you from meeting your comfort expectations in the home.

To calculate an approximate size for your HVAC system, you may use the following calculations:

Determine Square Footage

It might sound tricky, but figuring out the size of the HVAC system you need is pretty straightforward. Anyone can do it! The ploy is to gather information first and then apply a little know-how. To get started, you'll need to know a few numbers about the place you plan on installing the unit – including the square footage of each room and hallway, as well as the number of floors in your home. This is a great way to accurately calculate the size of an air conditioner or heat pump installation to keep things comfortable year-round.

Determine the Base BTU

A BTU, or a British thermal unit, is a measurement of heat. The BTUs measure the amount of energy required to heat or cool one square foot of an area. Your HVAC system has to produce a certain number of BTUs to sufficiently warm and cool your home. That number varies depending on the size of your home, but you can determine that number by multiplying the square footage in your home by 25 BTU per square foot.

Consider High Ceilings

When figuring out how many BTUs you need for your room, it is crucial to understand the role ceilings play in it. Flat roofs have one surface and are relatively simple to deal with, while vaulted or cathedral ceilings have multiple surfaces.

Base your room's recommended BTUs on the square footage, and then multiply by 1.25 for rooms with high ceilings. Rooms with ceilings higher than 8 feet should have at least 25% more BTUs than the recommended amount. These adjustments for ceiling height not only save you money but help simplify buying a heater that matches the appropriate temperature needs.

Decide which HVAC System to Purchase

Discuss the matter with a contractor when you have settled on an HVAC unit that satisfies your physical requirements. Your contractor will be able to calculate the BTU load required by your particular situation, given factors such as the size of your house. If your heating or cooling requirement falls between two sizes, go with the larger unit. That way, you'll be prepared for high or low temperatures on extreme days of the year.

The Bottom Line

HVAC units vary in size according to the square footage of the home, window area, number of inhabitants and materials used in construction and flooring. Your contractor will be able to determine what size unit is needed while looking at these factors, so there's no need to guess. A professional will make sure to take accurate measurements and design a system that is both effective and cost-efficient. Large floor plan homes will use more energy than smaller plans due to increased space. Ensure that you're getting a unit that is appropriately sized for the square footage of your home.