A costly HVAC contractor mistake
Watch out if you own a ranch style home with a packaged heat pump or gas pack on the roof. A common HVAC contractor mistake was to install the wrong type of elbow on the roof. An elbow is the curved piece of sheet metal between the heating and cooling system and the ductwork in the attic.
The different types of elbows, in order of worst to best, are outlined below.
1. Over-under elbow. Over-under elbows are worst type of elbow HVAC contractors can install. These were originally installed on ranch style homes and are still sitting on roofs today even with brand new AC units! The problem with these sheet metal elbows is that they reduce in size when going into the roof and choke the air off to and from the HVAC system. This causes major restrictions to the airflow, making the heat pump work harder and shortening it's useful life. The good news is that over-under elbows can be changed without having to replace the heating and cooling system.
2. Down draft. Down draft elbows are better than over-under elbows because the limited amount of exposed metal, especially in the hot Phoenix sun. However, the down sides outweigh the benefit of the reduced heat gain. The main downside is that the down draft elbow is also still restrictive to airflow (are you beginning to see a pattern here?). Having those restrictions will make a 5 ton heat pump only give 4 tons of air! During our energy audits we measure the amount of airflow restrictions in the duct system and time and time again we find these types of elbows highly restrictive.
3. Side-by-side. Even though side by side elbows have more area exposed to the sun and have more heat gain (yes they are insulated), the restriction is far less than the down draft elbow so the AC unit doesn't have to work as hard. That also means that a 5 ton heat pump will deliver 5 tons of air through the elbow! HVAC contractors need to be a little more experienced when installing side by side elbows because there are a few more measurements needed but it is worth the extra effort.
7/15/2018 11:57:48 am
Without a picture of a side-by-side, this isn't at all helpful.
8/25/2018 11:20:34 am
Thanks for your comment Haakon, I've uploaded some photos at the end of this post of side by side elbows.
12/6/2018 07:04:30 pm
Hey - awesome list. Definitely on the technical side, but I feel like this HVAC blunders needs to be spelled out for homeowners before it's too late. Thanks!
11/26/2019 05:11:38 pm
I would agree that this unit is set up right. The customer is being serviced by an honest company in this instance. Great Job! Would like to see more top end jobs done these days!
I admire what you stated about the significance of obtaining a roofing contractor that cleans up the garden and disposes of old roofing material. I think that finding a contractor that goes above and beyond with the assistance is great because it increases their good reputation. My mom and I are considering getting new shingles on our home, so we’ll be sure to contact a numerous roofing contractor that provides excellent service.
4/27/2020 09:39:40 am
Mistakenly i installed the hvac contractor on my roof and faced many problems because of it. This blog helped me to understand why i was facing issues with the same. Well written blog with the detailed description in the video. The video has helped viewers to know the consequences and after effects of the installation better. I have seen similar information at one place, you can also see on Shv.co.nz.
9/15/2020 05:06:50 am
These are some great things which give us clear information regarding the costly HVAC contractor mistake. I really loved it and thank you very much for sharing this with us. You have a great visualization and you have really presented this content in a really good manner.
5/28/2021 11:13:03 pm
I love the explanation of this HVAC heat pump and furnace cleaning. We really need to know which service you need when it comes to cleaning. Thanks for sharing this great information.
9/1/2022 06:15:07 am
Compared to other heating and cooling systems, heat pumps are more efficient. They use less energy and fuel to heat/cool your home, and some water pumps show efficiency rates of up to 600%. They also have a long lifespan of up to 50 years.
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