The Texas house is only 5 years old, but the air handler is in the attic and we are less than a mile from the Laguna Madre bay - the 3rd saltiest body of water on the planet. The air handler rusted away - it took in too much salt air and it's done.
So, we had to shop for a new system. We wanted something to be efficient and have a coastal warranty. We were looking at Bryant/Carrier because that's the installer that we have worked with over the years.
We ended up with a Carrier Infinity system. It has a web-enabled thermostat with a lot of monitoring between the units. We can control it remotely and monitor if anything is wrong. It will run in de-humidification mode for most of the summer. The coastal units were offered in a 3 ton and 4 ton configuration. It is a 17 SEER system. It was close to an $8000 upgrade and we wanted to make sure we were choosing the right solution.
We read a lot about Manual J (AC unit sizing) calculations and Manual D (ductwork) calculations. We bought an app to calculate it ourselves and used on-line calculators. We came out at 2.1 to 2.5 ton systems. The old unit was a 4 ton. The installer said a 3 ton will never cover a 1700 square foot house in a very warm and humid climate. It was only $200 more for the 4 ton unit.
We worked on this for days - lots of research - lots of opinions out there. We ended up reading this article and hoping that it just doesn't matter what we selected:
http://www.greenbuildingadvisor.com/blogs/dept/musings/saving-energy-manual-j-and-manual-d
However, there is the risk that the unit never runs in second stage and so we really aren't getting the higher SEER rating. More about SEER ratings here:
http://www.acdirect.com/truth-about-seer-ratings
http://askweldin.com/Evaluatingefficiency.html
We ended up with the 4 ton unit. Even though we think we could have gotten by the the 3 ton. And...we will never know if we bought the right one -- unless we buy another one to compare.
So, we had to shop for a new system. We wanted something to be efficient and have a coastal warranty. We were looking at Bryant/Carrier because that's the installer that we have worked with over the years.
We ended up with a Carrier Infinity system. It has a web-enabled thermostat with a lot of monitoring between the units. We can control it remotely and monitor if anything is wrong. It will run in de-humidification mode for most of the summer. The coastal units were offered in a 3 ton and 4 ton configuration. It is a 17 SEER system. It was close to an $8000 upgrade and we wanted to make sure we were choosing the right solution.
We read a lot about Manual J (AC unit sizing) calculations and Manual D (ductwork) calculations. We bought an app to calculate it ourselves and used on-line calculators. We came out at 2.1 to 2.5 ton systems. The old unit was a 4 ton. The installer said a 3 ton will never cover a 1700 square foot house in a very warm and humid climate. It was only $200 more for the 4 ton unit.
We worked on this for days - lots of research - lots of opinions out there. We ended up reading this article and hoping that it just doesn't matter what we selected:
http://www.greenbuildingadvisor.com/blogs/dept/musings/saving-energy-manual-j-and-manual-d
However, there is the risk that the unit never runs in second stage and so we really aren't getting the higher SEER rating. More about SEER ratings here:
http://www.acdirect.com/truth-about-seer-ratings
http://askweldin.com/Evaluatingefficiency.html
We ended up with the 4 ton unit. Even though we think we could have gotten by the the 3 ton. And...we will never know if we bought the right one -- unless we buy another one to compare.