how to size an ac unit to a house

Sizing your central air conditioning unit can be one of the most frustrating parts of the process of installing a new air conditioner. Customers that solicit price quotes from multiple companies are routinely given different sizing recommendations and different reasonings for those sizes. So how are you supposed to know what size air conditioner you actually need? I’ll give you some simplified guidelines for how central air conditioning units are sized here in Denver, but... The bottom line is that it’s not your responsibility to try and figure out what size your central air conditioner should be. Find a company you can trust, make sure they offer 100% money-back satisfaction guarantee in writing, and let them take responsibility for sizing the unit properly! The company you choose to install your new ac unit will use a long-form calculation called a Manual J Load Calc to determine the optimal size of your new unit. But it’s understandable to want a general idea of the approximate size your central air conditioner should be without going to an engineering class, and that’s actually a pretty simple equation.
Here in Denver, you can get a rough approximation of how many tons your central air conditioner should be by dividing the square footage of your home by 600. It’s important that you not include any square footage in the basement in this calculation, regardless of whether your basement is finished or not. Dividing your home’s square footage by 600 does not work for homeowners outside the metro Denver area. The 600 figure is higher than the figure that would be used in other parts of the country because it has been adjusted upwards to account for Denver’s higher altitude.small ac unit for one room Approximate Sizing Equation For Central Air Conditioners In Denverhow much does an ac unit replacement cost Example: 1,500 s.f. / 600 = 2.5 ton ac unit 1,800 s.f / 600 = 3 ton ac unit 2,100 s.f. / 600 = 3.5 ton ac unit 2,400 s.f. / 600 = 4.0 ton ac unit Over 2,4000 s.f. / 600 = 5.0 ton ac unitbest price on window ac units
Newer, more energy efficient homes can sometimes require slightly smaller units than the approximate sizing equation would suggest, but that depends on a number of factors related to the construction and style of home. Please keep in mind, this gives you a general approximation on sizing for your air conditioner. Your heating and air company should attempt to fine-tune the size by performing a Manual J Load Calc. The load calculation may confirm that your home needs the same size as the Approximate Sizing equation produced, or it could indicate that you need a slightly smaller size. If you are given a quote that recommends installing an ac unit that is more than 1/2 ton smaller than what the approximate sizing equation suggests, and that quote does not include a 100% money-back satisfaction guarantee, you are taking a huge risk. It’s pretty rare that a load calculation will suggest installing a unit that is more than 1/2 ton smaller than the size you’ll get from the approximate sizing equation, but if it happens, you’ll want the contractor to make sure you have sufficient return air to handle the extra cooling capacity.
To be honest, allowing any company that doesn’t offer a 100% money-back satisfaction guarantee in writing to install your new air conditioner is like rolling the dice. You have to cross your fingers and hope that they will install the correct size ac unit, as well as doing a good job on the installation itself. Without that 100% money-back guarantee you are basically on your own if there’s a problem. If you haven’t read it yet, check out our blog post titled How Does Size Affect The Cost Of A Central Air Conditioning Unit?If you're considering a ductless split system installation, you probably have some questions. Using highly advanced technology, Mitsubishi Electric Cooling and Heating makes some of the best ductless air conditioning systems on the market. These innovative cooling devices are highly efficient by delivering a consistent, quiet flow of cool air to keep you comfortable and conserve energy. However, split systems must always be properly sized to accommodate the indoor spaces they are designed to cool.
The primary advantage of Mitsubishi Electric ductless air conditioning systems is that you don't need the duct work required by a central air conditioner. Another benefit is that, unlike central air conditioning systems, ductless systems are much easier to install. Split systems consist of an outdoor unit and one or more indoor units (air handlers). The compressor and condenser coil are located in the outdoor unit, while the evaporator coil is situated in the indoor unit. A small hole of less than 3 inches in diameter is made in the wall to accommodate electrical wiring and copper tubing that connects the outdoor unit to the indoor unit. The outdoor unit transfers refrigerant from the compressor and condenser coil via the tubing to the evaporator coil in the indoor unit. Cooled air is then blown indoors by a fan that's virtually silent. The sleek and inconspicuous indoor units can be mounted on the wall or ceiling. You can regulate the temperature of each indoor unit with a remote control or a wall-mounted thermostat.
Multiple indoor units can be connected to the same outdoor unit. Each indoor unit can then be programmed to maintain a different temperature, thus creating separate cooling zones. This differs from central systems where the thermostat setting determines the temperature in every room. Proper ductless air conditioner sizing is essential for high efficiency performance and the level of cooling capacity. If the sizing is too small or too large, the system won't cool properly, and it won't operate efficiently. And if the system is improperly sized, if the indoor units are mounted in the wrong locations, or the installation itself is done incorrectly, you'll be left with an expensive problem to fix. Systems that are incorrectly sized and improperly positioned can seriously interfere with humidity control and cost a bundle in high electric bills. Sizing a split system will depend on existing insulation levels, the area you want to cool and on how many indoor air handlers you plan to include.
The more indoor units you want, the more precise the sizing must be. Because you're investing in a high performance system, technicians at Mitsubishi Electric Cooling and Heating recommend professional sizing and installation. That way, you'll know the job will be done properly and that your investment will be protected. Ductless splits cool a larger area at the same BTU level than do window air conditioners and portable air conditioners. Below is an approximate sizing guide: 350 square feet = 9,000 BTU 500 square feet = 12,000 BTU 750 square feet = 18,000 BTU 1000 square feet = 24,000 BTU 1250 square feet = 30,000 BTU 1500 square feet = 36,000 BTU The expert contractors at Mitsubishi Electric Cooling and Heating do not recommend installing a mini split system yourself. Although these systems are easier to install than central air conditioners, it's best to hire a licensed and insured contractor who employs NATE-Certified technicians. There are safety risks involved, and the installation process requires high-tech tools and specialized techniques.