Should I replace Forced Air with Hydro Air?

moneymm

my wife and I and kids all have bad allergies. we are buying a 10 year old house with forced air & ac ducts. the gas boiler is only 10 years old, and looks good. the 2 hot water tanks need to be replaced. the 2 AC air condensers need to be replaced (3.5 ton and 4 ton). one guy told me since they use R22, i will likely need to change the entire freon line, and maybe the air handlers as well.

so since im going to have to change the AC condensers and maybe the air handler, what is the best heating A/C solution i could put in/ switch to?

all the ductwork seems in great shape, and its a big 4,000 sq foot house. so im thinking i should 100% keep the ductwork and work with it.

Jamie Hall

What part does the gas boiler play in this system now?

I don't care for forced air -- I'll state that right up front. However, where all the ductwork is in place and seems in good shape, my own opinion (and it's just me) would be to replace both present A/C systems with heat pumps, suitably sized. This will provide cooling in the summer and heat in the winter, and newer ones are reasonably efficient down to remarkably low temperatures -- though I would ask where you are located, as that makes a difference.

The allergy problem is not related to the heat source, but the way the air is handled. You will want the new system to have excellent filtration -- probably HEPA and multistage, rather than simple media filters. You may even want UV on it. Also, humidity should be tightly controlled; you probably will want the capability to both humidify and dehumidify.

You should also consider providing controlled outdoor makeup air through a sensible heat heat exchanger -- but that must feed into the returns before any humidity control and filtration stages.

moneymm

thank you for feedback. i have no idea how the current gas boiler plays a part, i guess maybe i have hydro -air now? and it sends up hot water to the coild in attic and then through the handler and ducts?

there are 5 lines out of boiler, one for a radiant floor in bathroom, one for hw tank #1, one for hw tank #2, one for 2nd floor air handler and one for 1st floor air handler

so does that mean i have hydro air?

is this the best solution for me anyway?

pecmsg

Get the equipment thoroughly checked.

Over 1/2 the systems I see are Oversized on Undersized ducts.

John Mills_5

You have hydro air now. Great advice from Jamie. Lots of ways to improve the indoor air quality.

Jamie Hall

Yes, you do have hydroair now. More to the point, you are doing the bathroom floor with hot water radiant, and your domestic hot water with the boiler.

There is no reason at all not to keep those hydroair coils as they are -- they are not connected to the A/C except through the ductwork and some of the controls. Therefore, I would be inclined to keep that in operation, so long as the boiler is in good condition (you have had it maintained and cleaned and adjusted, haven't you?) at least as backup/cold weather heat for your HVAC system.

That said, I would still go for a heat pump or heat pumps, rather than replacing the air conditioner in kind -- why not, after all? -- which will give you all the heat you need in the shoulder seasons, leaving the boiler (which will be oversized, but it's there...) for the bathroom and the hot water. That you may want to change at a later date.

My comments on filtration and humidity stand.

The controls for all this are going to be a little complex. I strongly adivse getting a really good person to work on this -- this is not a job for just any HAVC company.

HVACNUT

All that ^^^ and 7.5 tons of A/C for 4000 st ft is ludicrous. You need a contractor who can size your new equipment properly.
With the existing A/C, going from R22 to 410A needs a new A/H anyway because of the oils, evaporator and metering device. So a correctly sized heat pump with 2nd stage hydro coil is a good set up for what you've got.
I just ordered an AtmosAir Madderhorn 1000 for my own home. One of my boys has asthma and struck out with UV lights. Customers I've seen who have it say they're living up to their claims.
Also have a Merv 16 air filter.

EBEBRATT-Ed

What @Jamie Hall said is good advise

Voyager

I do like forced air systems, but I still second Jamie’s advice.

A forced air system is the best way to address allergens. There are filters available to capture pretty much anything you need captured. The key is to find someone who understands advanced filtration.

moneymm

on Long Island, NY

it may be overkill i am not sure, but it was done by a reputable company 10 years ago, and here are more of the details. it has 10' ceilings on first floor, 1 room is 15x15 with 14' ceilings, 8' on second floor, the garage is 550, so really 3450 of living space but 3/4 of it is on the first floor which has the 10' ceilings. and its open to 2nd floor in large foyer area with 18' ceilings.

so basically if your starting from scratch on this house in NY but you have the duct work already in place. you would go with heat pumps outside, and new air handlers in the attic. and then get a heat exchanger?

thanks again.

HVACNUT

Basically the same set up you have now only heat pumps instead of just A/C.
First stage heat pump, second stage hydro coil.
You'll need 2 stage heat thermostats. Possibly 2 stage cool if its going to be a 2 stage cooling condenser.
Go over all your IAQ concerns with the contractor.

pecmsg

HVACNUT said:

Basically the same set up you have now only heat pumps instead of just A/C.

First stage heat pump, second stage hydro coil.

You'll need 2 stage heat thermostats. Possibly 2 stage cool if its going to be a 2 stage cooling condenser.

Go over all your IAQ concerns with the contractor.

and get a larger return with the media filter!

mikeg2015

Ya, that’s still oversized by Not surprising. Shouldn’t need more than 5 tons total in your climate. Humidity control is CRITICAL for allergies. The hot water zoning is great. Ideally you wan tooted water, high delta T and lowest airflow possible for comfort. You want less air movement.

You might consider a whole house dehumidifier that’s als ventilating and can constantly bring in fresh filtered outside air all the time.

Is this new construction?

Wish I lived cover. Sounds like a fun project.