Thread #2..........Variable Speed A/C Units
 

Variable Speed Unit owners......................do you have Zones???
How much was the up-charge??

With our 2-Stage unit, we have zones set up.
Largest benefit is cooling the bedroom(s) only at night (not the whole house).

If we want to continue with zones, SunKool said that would cost an additional $4500.
(current zone equipment would not work with a new variable speed unit)

:shocked:

We have a 4-zone system. It is great particularly at night when there is no need to cool the whole house but just the bedroom.
I only remember the total cost when we replaced our whole system and included the 4 zone to a grand total $14K. The up cost for the zone system was in the $3-4K range.

Right, so with a variable speed system such as the Carrier Infinity, you need a special zone damper control that's compatible with the system which can variably open and close the zone damper vs just being full open or full closed. In your situation where you are just using it at night, this isn't a concern but the way the system is designed it trys to even out the temperature and if it's zoned then it needs to variably control those zones as well.
I have no idea what these controls cost and the labor to replace your existing control.

Why not just replace with a new two-stage unit so you can use the existing dampers? Seems like that would save a lot of money while sacrificing just a little bit of efficiency.

I always hated spending dollar to save dime.

:thumbup:

Would you spend the dollar to be more comfortable?

Oh I agree..................just fishing to see if I'm missing anything.

76 is 76 no matter how it gets there.

rather than cooling in zones, you need to do a performance test on your existing system.. People are installing high Merv rated air handler filters reducing cold air flow.. Evaporators also become neglected, and should be cleaned.. Before you spend thousands, spend a few hundred and create an efficient cooling system..doing basics with a reputable AC company, makes your compressor smile

I would spend 100 dollars to be more comfortable. But I am already comfortable. My single stage heat pump maintains a constant temperature in the house that is within one degree of the thermostat setting, the humidity is always acceptable, and it is so quiet that I don't even know when it is running.

Also, I don't understand the need for a zoned system in a single story house with no insulated interior walls. I maintain a constant temperature throughout the house and my electric bill is usually less than $100. Cooling down the bedrooms at night and not cooling the rest of the house would make me less comfortable, not more comfortable.

had flow test, annual maint/cleaning, etc.,.............basics done

we already have zones, significant savings for over five years.

In theory it sounds good. But the cost? You will never recoup your money. Ever!

With my Bosch units I had Zone setup. But that doesn't necessarily mean that only the bedroom or any room in the house can receive air. What that means is it keep the temperature balanced in all rooms and run room goes unbalanced the air conditioning comes on. So you may have the right temperature in the bedroom that you want but the other rooms are probably going to be cooler. Think about it to truly have a zone system, you need to have certain trunks open and shut at different times. So maybe that's where the cost comes in. But I've never heard of that happening. To open and shut different zones forget the desired temperature seems like an expensive mechanical issue. The best system you can buy out there hands down is a Bosch.

My home is 1200 sq ft. I never open windows or leave doors open during the humid season. I want to maintain a steady humidity of around 50% and a temp of 75°, day and night. I live alone, so all doors between rooms are open all the time. My electric bill for May was $119. The bill for April was $85. In a home like mine, multiple zones would save me very little, as there is never a time when I want the living room temperature to be different from the bedroom. I don’t want the living room temp rising multiple degrees in the night while the bedroom is cooler. For me, I don’t think the cost of a multi-zone system would be paid for in the years I have left. If I get too warm, it’s easy to turn on the ceiling fan.

Sounds like there would be no reason for you to upgrade. But that is definitely not true for everyone.

My house does not stay at a uniform temperature throughout the house, not even close. One front bedroom gets a lot of sun and gets warm. Another bedroom abuts the garage and has a sort run from the air handler to the register. It gets cold. The one thermostat sits in the middle of the house and has no idea what is going on in distant rooms. Now you can of course manually adjust the dampers to try to make everything as uniform as possible and I do, but it is crude and its not dynamic.

Also, the occupants of different bedrooms in my house like different temperatures. So that complicates things further.

I have a single stage on-off system, I wish I had thermostatic control over the dampers. But I don't. I am not getting rid of a perfectly good nearly new single stage system and spending a lot of money to upgrade. But I would if I could do it economically.

Been a loooong time
 

It's been a looong time since I was in the HVAC business, but if you already have a 2 zone system why wouldn't the new equipment work? The zones I assume are set up with your ductwork throughout the house. It used to be done with electrically operated dampers to control where the conditioned air flows. If that's the case, I would imagine the new equipment would not matter if it's variable or 2 stage or single stage. Things may have changed in how systems are zoned but that seems like a lot of money for an upcharge to a 2 zone duct system that is already in place. Good luck.

If he goes with a single or two stage unit then he can reuse the existing zone controls. If he goes with a variable speed inverter system then he needs the zone controls that can be variably opened and closed that work with that system vs the existing zone controls that are either Full Open or Full Closed.

Some companies don't want to do duct work and always charge more others charge less for the same thing. I would get a couple more quotes.

Sent PM.