I went online to a site that has a form for listing data about a home that will make it possible to calculate the BTUH gain. Mine came to 25,443.704 BTUH gain. If you figure 12K per ton, then my home would only need a little over 2 tons for heating and cooling. This was using a 20 degree differential between outside and inside air. I don't know id this follows Manual J very closely, but it seems like the total might be a little low. Am I missing something? Butch
Yes, it does. I thought the form was calling for an average low. We see temps in the 20's occasionally, but it's unusual for it to last more than two nights in a row. The form I was working with only offered 3 choices for temp differentials- 15, 20, and 25 degrees, so I chose the one in the middle. Butch
The website says this about the program " This is not a Manual J program so it does not use the Manual J standard and would not be considered Manual J compliant." Too bad you didn't get this one HVAC Calc only $49 for DIY. You need to have confidence in the Heat Loads. Not sure what to tell you.
I haven't spent any money yet. I'm hoping I can find an installer who will have the right info to perform the test. Butch
Yes you are, gain pertains to cooling load, loss (heating load)is usually a different number entirely, however that does not mean you won't end up with a 2 ton, we do not have enough information to tell. If you want to fill out the info section at "www"dot do it yourself geothermal dot "com" I can compare you to houses in our archives and get you some ball park numbers.
Joe, I filled in your form, but I'm not sure I gave the info you need about my existing furnace. Butch
I am not familiar with your area of course, but swag suggests <3 tons of cooling load with < 1 more ton of heating load. While counterintuitive heating loads are often higher there due to a higher delta t requirement. It is quite possible the 2 ton is a good fit with auxilliary heat on the coldest days. Moving forward, local design practices are for a reason, so we need to see what the Dallas area pros suggest. I don't know if Bill is out there, but I believe he had a contractor he was extremely leased with. Good luck, Joe
Thanks, Joe. There is a term that I am not familiar with. What does Delta T deal with? And, yes I would like to hear from Bill if he found a dealer in Dallas who could help. So far, I have been somewhat confused by info I've gotten from dealers in this area. Butch
delta T is temperature difference, or in this case difference between outdoor temp and desired set point.
