New Construction, ICF home, no room for ducting: mini split VS high velocity?

[ET_Phone_Home]

Hello all,

Building a 2000 SF home and 300SF detached studio in upstate NY.

* ICF construction, radiant floor heat with propane boiler.

* Slab on grade, no attic; Virtually no room for conventional ducting (the home is modern in design).

* Home is two levels: master bed/bath on 2nd level, with guest bed/bath and large, open-plan living/kitchen area on ground floor.

* Would like to upgrade to geothermal in the future.

* Price is an object.

Question: Initially, we decided on the Mitsubishi mini split system for only the bedrooms and one in the detached studio.

However, I am concerned about air quality in an ICF home.

Because we have no place to put a conventional HVAC and ducting in the design, I was wondering if High Velocity would work for our situation? It seems to me it would provide cooling and the air filtration I am looking for.

I talked about this with a mech engineer friend of mine and he said HV is not recommended for new construction, only renovations. The systems are very pricey and air flow is loud. He said the only way to deaden the noise is to install many more outlets per room.

I'd appreciate anyone's opinion in the What-Would-You-Do-variety.

Do I stick with mini splits in the bedrooms? In that case, how do we address air quality? Could we just install localized ERV's in the dropped ceilings of the master/guest bathrooms to vent out to their respective bedrooms?

OR

Do I spring for the HV system and deal with the noise (which should only really be used for cooling purposes, since the home has hydronic heat)?

Thanks in advance for everyone's help.

[BobbyBJr]

Some of the minisplit air handlers have a provision for outside air, but a ERV might be a better choice. Even with the HV system, you are going to have to have enough room somewhere for the air handler and some ductwork. Properly installed, noise shouldn't be much of a issue.

[Cold Feet]

* ICF construction, radiant floor heat with propane boiler.

Look very closely at relative energy prices in your area before committing to a propane boiler. In my area, propane and electricity cost about the same per kwh. Electric and propane boilers would cost about the same to operate but electric boilers are much, much cheaper than propane boilers.

If you're in this kind of energy cost box and don't have access to natural gas, the only way to get out from behind the energy cost eight ball is with a heat pump.

However, I am concerned about air quality in an ICF home.

You will need some form of mechanical ventilation to get acceptable IAQ in new, well sealed, construction.

I would go for an ERV with dedicated 4" ventilation ducts to every room. Use a multi-split heat pump for cooling in critical rooms and heating in the shoulder seasons.

There are large multi-split heat pumps available that can cool an entire house.

[beenthere]

Your friend has never seen a properly installed HV system then.

They are also used in new construction applications.