The last thing anyone needs during the hottest or coldest months of the year is a failure of their HVAC system. The outdoor temperature can vary a great deal over the course of a year, and we rely on our HVAC systems to keep our indoor spaces comfortable. Many homeowners installing a new HVAC system or replacing an older unit don’t understand how important it is to get the right sized system. In fact, if the HVAC system is too large or small for the home, it can lead to a number of problems, such as poor performance, larger energy bills, and even health issues. Let’s take a closer look at how an HVAC system should be sized to work efficiently in your home.
Why Does an HVAC System Need to be Sized?
When you think about choosing an HVAC system for your own home, it’s essential to understand that there is no one size fits all solution. Many people make the mistake of purchasing the largest HVAC system that they can afford. But, this isn’t a smart decision, an HVAC system that’s too large for your home is just as bad as a system that’s too small. If you have an oversized HVAC system, you may notice short cycling, when the system turns on and off again quickly, and this is caused by the home cooling down too quickly. A larger HVAC system will also cost more to run, and in many cases, a smaller system would be a far better option.
How is the HVAC Unit Size Determined?
There is no standard formula to work out the exact size of HVAC system that you would need for your home. After all, every home is different, and there are a number of factors that will determine the size of HVAC system that you need. In order to find the appropriate HVAC system for your home, it will be necessary to carry out a load calculation. There are free online tools available for this, but they are not very accurate, and they don’t take into account many aspects of your home. It’s a better idea to contact a local certified HVAC professional to carry out a load calculation for you. They have the skill, experience, and tools to find out the size and type of HVAC system that you need for effective and energy efficient heating and cooling.
How is a Load Calculation Carried Out?
An HVAC professional will look at many areas of your home to help them make an accurate load calculation. Let’s take a look at five of these factors in more detail below.
- The Age of Your Home
If you have an older home, you may not be enough ductwork or ventilation available to meet the needs of a new modern HVAC system. Another key consideration is the condition of the electrical systems, and it may be necessary to bring this up to code to meet the revised power demands. If you have an existing HVAC system that you want to keep running for a few more years, it may be possible to carry out an HVAC retrofit. This could improve the efficiency of your HVAC system, but in many cases, it makes better financial sense to install a new unit instead.
- The Placement of Your Home
Your home placement will have a major impact on how hard your HVAC system will have to work. Even a difference of 90º can affect the size of HVAC system that you would need and how well it can function efficiently. As an example: If you get a great deal of sunlight flooding into your home during the summer months this will heat up your home significantly, and your HVAC system will need to work much harder. Installing appropriate window treatments and creating shade can help you to keep your rooms cooler on hot days. If your HVAC system has to work too hard at cooling down a hot room, it’s more likely to fail, and the useful lifespan could be reduced.
- Home Insulation Levels
When most people think about home insulation, they typically think about keeping heat in the home during the colder months. But, insulation is also important to prevent cold treated air from escaping and keeping it in your home. The type and amount of insulation that you have in your home is a major factor in how well you can maintain a comfortable temperature. The load calculation will determine if there is enough insulation and more can be added when the ductwork for your new HVAC system is installed.
- Window Considerations
The type, size, and the number of windows that you have in your home will be a major factor in the size of HVAC system that you need. During the day a window can receive a great deal of sunshine, and this will cause your home to heat up. So, if you have a large number of windows facing the sun, your HVAC system will need to work extra hard to cool the room down. This is a boon in winter when the extra free thermal energy comes in handy for heating purposes, but in summer it’s a real problem. As we mentioned above, window treatments can cut down the sunlight considerably, but you have to remember to close them during the hottest parts of the day. If you have single pane windows, they don’t provide much thermal insulation compared to double or even triple paned window types.
- Weatherstripping Windows and Doors
The windows and doors in your home may have good insulation levels, but this isn’t especially useful if there are gaps around the openings. If you want to get the maximum efficiency from your HVAC system, any gaps where air could escape must be sealed. Adding weatherstripping around every window and door in the home will help your HVAC system to work better, and a lack of weatherstripping will affect the load calculation.