We are happy to help you in any way we can. Sizing a mini split is not as simple as measuring for square footage and matching that to a certain BTU system. While usually this gets you pretty close and sometimes works out perfect, there are cases where you need a larger or smaller unit than you may think due to insulation, windows, trees, room shape etc. and we can try and help you make the right decision based on the information you provide. You can always hire a contractor to come out and perform a load calculation which will also help you get a good idea of what size mini split you will need for your application.
Mini split sizing vs central hvac sizing.
When sizing a mini split you will work with each zone separately. Even if you're using a multi-zone system you will still have a single individually controlled air handler in each zone. Because of this you can match up each zone with the perfect size air handler to do the job and not worry about over sizing to be able to handle hotter areas of the house. With central air you need to be able to cool the hottest room in the house to a reasonable temperature while still cooling the rest of the house. Many times you will need to keep the rest of the house colder than necessary just to keep the hotter rooms bearable. This is less comfortable and less efficient then a mini split where you only have to use more power in the rooms that need it and not waste energy on the rest of the house when it's not needed. You will begin to see the savings almost immediately on your monthly power bill.
What's the best way to determine the correct ac sizing for your home?
The best way is always going to be having someone come out in person. When talking over the phone the person helping you is only going off of what they hear. Having an installer with good experience come out and look is certainly worth it if you want to be certain you get the right size unit. An installer will see things you may not think to share over the phone and they can use there instincts to get you the correct size more accurately than just over the phone. They may try to sell you an air conditioner marked up to make them some extra money. Before you buy from them compare the prices of what they're selling with a comparable unit from us. We will almost certainly beat their prices and then you can still use them for the install if you like and hold them to the labor prices they promised you hoping you would buy a unit from them. This will save you money all around, ensure your system is installed properly, and keep your factory warranty in tact.
Does all this apply to heat pump sizing as well?
Absolutely, heat pumps need the same attention in sizing as A.C. only models. You don't want to install a unit in the summer and come winter time find out its not enough to keep up. Also if you have a certain size A.C. unit don't assume you will need the same size heat pump! Depending on where you live you may have mild summers and severe winters in cases like this you will certainly need a higher BTU heater than you needed for you air conditioner. Same goes for people in hotter climates. If you needed a large A.C. unit for the summer but don't get extremely cold in the winter there is no sense wasting money on a larger heater if you don't need it.
But let me guess you found a mini split sizing calculator?
While this is better than just guessing with square feet you are still taking some what of a risk that you could miss something and get the wrong size. Think of it this way, if you have someone come out and do a sizing for you then you have someone to go to if there is a problem. If you choose a unit on your own you pretty much have no options other than buy the correct unit and maybe sell the other. We always encourage making 100% sure that the size of mini split you choose is going to be exactly what you need. Over sizing or under sizing a unit is just as inefficient as heating and cooling rooms you don't use.