Originally Posted By: grizzley This post was automatically imported from our archived forum.
I purchased a house and it had a room built onto the existing home. The addon did not have heat/air running to it.
Since I know NOTHING about HVAC except how to turn it ON and OFF, I decided I would run vents to that addon. So, I get under the house and put my good eye on things.... Well, I have since learned some of the "lingo" so I will use it...
The plenum is where I hooked into. I put a 8" connector and then ran that via a 5 foot "flex" duct to a "Y". From that "Y", I went to 2 vents.
I managed to get the vents installed and air blowing through them after about 4 hours of banging my head on floor joists.
Now, OBVIOUSLY, the house does not cool down on 90 degree days. The AC runs all day long and the house only gets around 78 degrees.
What is the best thing to do here? I think I might look at replacing the unit that sits outside that has the fan on top. I think its called the condinsor? I have no idea what model # it is or what ton it is. The only thing on it is the serial number (5182J10555) Lennox, and after reading, I think that is a 1982 model, but have no idea on the tons for it.
I would have NEVER messed with it but every HVAC place I called said "Maybe we will get to it in 3-5 weeks, if things are slow at that time". New construction gets their business, not the average house.
So, is my thought process correct that I need a larger unit that sits outside? And, is there a way to tell the tons of the current on by the serial number?
Originally Posted By: jschwartz1 This post was automatically imported from our archived forum.
Your are correct. You messed up. A ton is equal to @ 450 square feet of space. 900 sq = 2 tons etc. Please proved the model number of the lennox and the total sq ft of the home.
Originally Posted By: grizzley This post was automatically imported from our archived forum.
Hey Jay, thanks for reassuring me that I messed up After I saw the performance of my efforts, I thought I did…
I don't have the model number. All of the text on the stickers has worn off. The only thing I can read on any side is the serial number (posted earler).
Originally Posted By: Blaine Wiley This post was automatically imported from our archived forum.
There are many more things that go into a system design for a house than the sq. ft. size. Although 450 sq. ft. might be a general rule of thumb, it isn’t accurate for all areas.
The air volume, sq. ft., basement, crawl space or slab on grade, R value of the insulation, etc. all factor in to the HVAC contractors design. I have seen houses that one ton per 900 sq. ft. was adequate and houses where 400 sq. ft. was not.
It is also bad to have a unit too large as the house will cool to quickly to remove the humidity.
I would advise you to have a reputable HVAC contractor come and do a check for you.
Originally Posted By: rbennett This post was automatically imported from our archived forum.
Blaine
Your post is right on I hope grizzley has a chance to re read your post
78 with 90 plus outside is not bad if the house leaks like a tent like many houses do in central FL
I can cool the house with a 100 pound block of ice if the house is small and made out of the guts of a beer cooler.
Back to Blaine's post -- More air will solve the problem but do look at spending some $$ to keep the cold in and make sure that the HVAC unit is in the shade and working properly
Trust me a lot of people would kill for 78 degrees
----- I added power attic vents --- HVAC is new 4 ton all new duct work -- House is 1925 two story no insulation - 75 degrees is not a problem in central Fl - YET -- DONT want to push it any colder or the unit will take off across the yard.
Will be adding some insulation as time goes on
Remember it is very hard for even the experts to compute all the variables
Just don't add tonnage without trying to stop the leaks first
Originally Posted By: grizzley This post was automatically imported from our archived forum.
rbennett wrote:
Blaine
Your post is right on I hope grizzley has a chance to re read your post
Yes, I read it and will be calling a professional to come out and install what is needed.
The house is pretty tight. It has new vinyl windows and new siding and was wrapped (again) with Dupont insulation when the siding was added; new exterior doors were also installed. Of course, the house has it's original insulation also. So I feel it is pretty well insulated.
Before I cut the holes and added the two new vents, the house would cool to 70-72 on a 90 degree day. At night, I have set it as low as 65 and it gets that cool.
I guess the added space is just too much for the outside unit now. I'll run it day and night, set on 68 degrees until it pukes it's guts out. Hopefully a service company will have the time to come out before then though.
Originally Posted By: kbowles This post was automatically imported from our archived forum.
LMAO @ Jay,
Thats right, go ahead and suggest 1 ton per 450 square feet...........might work in Florida. Did you even find out where this person lives? Heck if he lives in Wisconsin, do you think that rule of thumb still applies? Sizing a unit requires a Manual J load calculation to be performed on each and every application. Rules of thumb end up in litigation when mold starts popping up. Just my humble opinion.
After I saw the performance of my efforts, I thought I did…