To fully understand why some parts of most homes are either too hot or too cold. Or why one room is always hotter than the rest. You first need to understand what heat load is. Heat load is how much cooling or heating is needed to properly heat or cool a particular room, usually measured in BTU. Everything from square footage, how many square feet of windows are in the room and what side of the home they are located on play a factor, ceiling height, appliances and your zip code come into play. Most contractors are not properly sizing furnaces or air conditioners because they size based solely on square footage which does nothing for un even temperatures and they do not run the proper load calculation tests. Now, some areas of homes have a lot more heat load than others. Some examples are rooms with east or west facing windows, rooms with high ceilings or even rooms over the garage are always uncomfortable because it has heat coming up from below and usually 2-3 of its sides can be to the outside. Any of these conditions would cause that room or areas to warm up faster than other areas in the home with less heat intruding in or being generated.
Now that you understand how some areas warm up faster than others. Ask yourself is the problem that the unit runs or is it that the unit doesn’t run enough. Imagine if your motor stayed running longer always circulating air through the home. The rooms with more heat load would never get a chance to warm up since the entire homes air would always be mixing. The result would be an entire home with the exact same temperature. So, the short explanation is a single speed motor that turns on 100% and off then on 100% again is one reason and also the most overlooked problem in the US causing uneven temperatures in rooms. It’s the off cycle that allows the rooms to warm faster than the others.
Ductwork is also a major problem in the US as 93% of homes have major duct leakage. That number is taken directly from the US department of energy website and also energy star website.
In the first paragraph I explained how a heat load calculation determines how many btus are required to keep a room cool or warm. The ducts are sized to deliver that exact amount heating or cooling. But then 93% of ducts leak so wherever you leak air into the attic is less delivered into the home. Basically we size a duct to deliver enough air to cool a room but after leakage there may not be enough left to properly cool or heat a room.
A sure sign of leaky ducts is to open an inside door and look at the hinges if you see a black dust trail, you have leaky ducts.
The trail is caused by uneven pressures because the return is sucking out say 2000 cfms of air from your home then you pay to heat, cool and filter that air that then gets blown into the leaky duct system. So if 10% of the air leaks into the attic your only delivering 1800 cfms back into the home so its now in a negative pressure causing air to be pulled in through anywhere it can find it. Air will always take the least path of resistance.
Leaky duct are major causes of poor indoor air quality, drafts and uneven temperatures, allergy symptoms and even shorter equipment life it could also more then double the HVAC portion of the energy bill.
Some tricks for home owners to fix some of these situations are:
Install a Variable speed motor $500.00 for the part plus 2-3 hrs labor. This motor will save them approximately 50% of what they’re current motor uses it will also run quieter and stay running longer circulating air through the entire home always blending the home air and keeping temperatures even. Most local power companies are urging homeowners to get variable speed motors installed and most are even offering rebates that could pay 100% of the cost of motor.
There are many ways to fix the duct balancing problems. A contractor can install dampers to push more air to the areas that need more air this can be done in less than an hour. Something a homeowner could do is to remove the vents of rooms that are getting too much air and restrict the vent or duct pushing more air to the other areas of the home that are not restricted. A homeowner could also crawl through their own attic and paint all the duct connections with duct sealant ( can be bought at any home depot or lowes for around $40 a bucket I suggest 3-4 buckets to seal an entire system. Just simply cover every connection and when it dries the entire duct system will be sealed and we will no longer be drawing in that hot dirty un-filtered attic air.
Sealing duct work is hard and dirty but if a homeowner is willing it can be done by them or any educated contractor could do it for around $800.00 But this will lower the energy bill around 5%-30% depending on the size and number of leaks in they’re system.
If a homeowner was to get a variable speed blower motor and completely seal all they’re ductwork, they would have a home with even temperatures, clean air, and energy costs could go down by as much as 25%
Other ways to save energy is to:
• Try and keep all doors closed and keep window coverings closed as much as possible especially those east and west facing windows.
• Installing a smart thermostat can save money by turning the unit off when its not being used. Always remember every time we can shut off the compressor is money saved. A programmable smart thermostat can shut your system down when you forget.
• Get your system checked by a professional at least once a year
• Spray the outside condenser coil with a garden hose once a year (will lower power bill)
F.Y.I. we have variable speed systems with variable speed cooling and heating capable of keeping the entire home to 1/10th of a degree to where they set the thermostat and that’s year around it does this by never shutting off instead it will just rev down to 25% and keep the air moving there’
s no way to have a higher level of comfort and energy efficiency as when reved down to 25% the motor is using 85 watts of power less than a 100 watt light bulb.
We have many more tricks and energy saving solutions. I’d love to share them with you anytime.
Our company and family has been servicing air conditioners, heaters, refrigeration since 1969 we are licensed, insured and many of our technicians actually teach air conditioning at the college on there spare time.
I also wrote a how to book for ac repair. It will be published soon on an app and online. The repair matrix is a follow your own ending format basically it can take any homeowner or service professional from start to finish, how to diagnose an air conditioner and repair the problem. After 20+ years repairing air conditioners I realized I had a procedure, an order if you will so I put it on paper as an if this then you do this format. The repair matrix will revolutionize this industry and no longer will a contractor be able to lie to homeowners because with this app the homeowner will be able to easily and within 7 steps or less fix or at least diagnose there own ac.
Stephen Gamst “ author of the repair matrix “
Las Vegas Air Conditioning Inc.