Installing a new system and so many questions

[FilmYak]

Installing a new system here in LA. Met w/3 contractors. The one I liked best has great reviews on angieslist and did a MUCH more thorough inspection of our current system and had great ideas on how to improve it.

We're getting rid of our 3 1/2 ton system, and big question is trying to figure out if we should go with a 4 ton or upgrade to a 5 ton. More specifically, a 4 ton with zone control, or a 5 ton without zone control are similarly priced. We've got a 2 floor house, bottom stays fairly cool even in summer, top floor can easily hit 90 degrees with our crappy current a/c system on. Not sure which approach is best, blast lots of air in or use less air in a smarter way.

Also, this is an Amana system. Any thoughts on a well installed Amana?

[beenthere]

What size, is best answered with a load calc. You can do your own, if you can't find a contractor that does them
HVAC Calc (http://hvaccomputer.com/talkref.asp)

Increasing size to a 5 ton. Won't do much good, if your duct work isn't fixed. If you have a 3.5 ton now. Your duct work isn't big enough to handle 5 tons.

Might want to consider 2 systems. One for the first floor, one for the second floor.

Nothing wrong with Amana.

No brand works right on undersized duct systems.

[FilmYak]

Yeah they'd replace ducts and electrical to handle the 5 ton unit too. Our house would be 4 except it's so energy inefficient (old construction) that we're kinda of on the cusp of a 4 or 5.

[beenthere]

Yeah they'd replace ducts and electrical to handle the 5 ton unit too. Our house would be 4 except it's so energy inefficient (old construction) that we're kinda of on the cusp of a 4 or 5.
Why waste money on a 5 ton system. And pay high energy cost to use it. When you could improve the insulation in the attic.
Seal your old windows and doors. Seal your receps and switches. And reduce the cooling and heating load. And save money every year.

[FilmYak]

Why waste money on a 5 ton system. And pay high energy cost to use it. When you could improve the insulation in the attic.
Seal your old windows and doors. Seal your receps and switches. And reduce the cooling and heating load. And save money every year.

Because we have no attic. We have a dark, flat roof with maybe 1/2" of insulation. Because we've tried raising the roof height to add insulation in there and the city is fighting us every step of the way. Because we need double pane windows but those cost a fortune for any house, and more so for our house with lots of picture windows.

And because our air conditioning unit died and needs replacing and we may as well get an entire new system that is vastly more efficient than our poorly maintained, poorly installed (before we bought the house) 15 year old existing system -- which moves it ahead of all other possible fixes, since we have zero a/c now and the Santa Anna winds are scheduled to start blowing this weekend.

And because the 5 ton system is similarly priced to a 4 ton zoned system.

So back to the original question, I have no idea what kind of performance difference those two would give, or what operating expense difference would be. How vast a difference is it? I know it's hard to quantify, but trying to feel out the process.

[dash]

If designed and installed correctly,four tons wth zoning will cost less to operate,service and eventually replace.


Far superior temperature control between floors,so you'll be more comfortable too.

Make it a two stage,4 ton and you'll really love the cost to operate and the comfort!

[FilmYak]

Great. Thanks!

If anyone has opposing views, I'm all ears, but that's definitely helpful information. Appreciated!

[beenthere]

Get a load calc done, and find out what size you really need.

caulking around your existing windows, and your receps and switches, is a low cost improvement. And can make a world of difference.

[RyanHughes]

we're kinda of on the cusp of a 4 or 5.

According to a load calc, or your contractor's best guess? The ductwork replacement should help tremendously in and of itself. Now the task is sizing the unit properly. Any brand, zoned or non-zoned (though zoned has its comfort advantages), sized properly for capacity and ductwork, should make a world of a difference. And I hope it does for you.

[green jumper]

Saying 4 ton this 5 ton that doesn't make much sense if you don't know what you really need. 4 ton + zoning isn't going to help if you need 5 tons of cooling for the house. Zoning is a comfort issue and should be considered separately then how much cooling you need and zoning wont help much if your ductwork is undersized anyway.

Find out what size equipment you need
Find out the condition of your ductwork and what repairs or upgrades will need to be made. is it under sized? if its not is it sized right? many people think they need to upgrade there ac when in fact there ducts are the issue.

If your budget allows it then do zoning and iaq, if your budget doesnt allow it you might mention to the contractor that in the future you would be upgrading and if theres any installation work they can do to make the proccess in the future easier and less labor intensive you might want to have that done now.

[FilmYak]

Installer did not run a load calculation, he's very willing to, but says the result will say we need more than a 5 ton system. From what I've researched I absolutely believe him, our house is wonderful on many levels but awful when it comes to energy efficiency. (He's got a similar style house and told me what he's done to improve his place, which is what we want to do but as we're in the hills, we have more restrictive building codes here that "the flats" aren't subject to. So his roof is now insulated, ours isn't. The weather stripping etc is something we definitely need to do, but won't be enough.

Basically we have an amazing hill view, but with massively large (and very old) windows, and almost no insulation anywhere in the house.

He DID do a calculation on our duct work and it will handle a 5 ton system if we add one more duct and enlarge the return, both of which are included in our bid (as is updating the electrical system).

Reason we aren't going over a 5 ton system is cost... as he correctly points out, anything is better than what we have now. In the summer it costs us around $400 month in electrical bills, and that's for a house that still hits high 80 degrees in afternoon.

I like the idea of holding off on zoning and adding that later as an option. 5 ton system with zoning is just price prohibitive.

Even though the 5 ton is more $, he's saying the 4 ton with zone system will probably be better for our house. Really a huge temp difference between our two floors (stairway in dead center of house, two half stairs with a landing, so it acts as a very large chimney in middle of house that sends all the heat to the wide open upstairs room with only a single vent. Whichever system we pick, a 2nd vent will be added to that room, and leaky ducts will be patched which will greatly increase air flow in there.)

[FilmYak]

PS - I think the fact that all you pro's are so helpful on this site is fantastic. Thank you all!! You've kept me from going to a lower end installer that didn't seem to do his homework and moved to a (sadly more expensive, but) much better and more thorough installer.

[green jumper]

It smells fishy, if your house does indeed need more then 5 tons of cooling are you convincing yourself you'll be ok with a warm house during hot days? Why are you taking his word for it, I'd want to know the numbers personally at least you'll know exactly what your going to be getting and wont be surprised when its 100 degrees and your house is 80 and you think it should be 72. As a contractor that would be the first thing I'd want to know to save on service calls down the line if this was a initial concern of the customers.

I wouldnt spend all this money and rush into something to get some cooling only to find it doesnt perform how you want it. If you have a house that needs more ac then residential systems can provide and you have unevenness due to floors why not two systems and scrap the zoning, or find out how much cooling you need per floor and put a system that'll serve that floor in now and then do the duct mods and add the second unit in the spring you'll be uncomfortable either way but this way your paying for a smaller system and progressing towards a more comfortable home.

Trusting someone based on there word would worry me I'd like to have it in writing even if it cost a bit extra personally.

[FilmYak]

Hmmm. Food for thought.

Main reason we're not even considering 2 systems is cost. So even if it says I need more, there's no way I can pay for it right now. The idea is to improve on what we had. I'd probably keep living with my older system if it hadn't have died yet again, this time with a massive leak. Been wanting to upgrade for some time and with at least a little $ coming from home warranty policy, it feels like it's time to swap it all out as opposed to keeping leaky ducts and a poorly installed furnace attached to a new, lowest-model possible compressor.