The heating and cooling system for a house depends on many factors. You are best off consulting with someone local that knows the house's design and other factors.

Hi, Rose,

To be sure, any input houzzers can provide is limited by the fact that we don't know your specific objectives for space conditioning of your home nor do we know the particulars of your home--especially the heating/cooling loads by room.

That said, in general, a bonus room over a (unconditioned) garage is a good candidate for a separate zone of control because it will heat up faster and cool down faster than other living areas. The basement is a good candidate for a separate zone, too, because it doesn't typically have a large heating or cooling load and it typically needs dehumidification even when there is no cooling load. Zoning the main part of the home would be driven by comfort considerations.

In discussing zoning with your contractor, you should aim to answer the following questions:

1. Do we need to zone? (usually driven by comfort considerations.)

2. What should be zoned? (usually comfort and/or relative humidity considerations.)

3. How will it be zoned? (either zoned from a single variable speed air handler with zone control dampers or by installing dedicated units for each zone or some combination of the two.)

I agree this cannot be answered by us IMO listen to your HVAC pro since they have all the info. BTW I dislike bonus rooms so have a purpose for that space and then that will help decide what you need for heating and cooling.

How you plan to insulate and seal the spaces can have a big impact on hvac. Minimum code vs. passive house for example. Anyway, get more bids.

Sounds like you got a good HVAC person with experience. You will not be happy trying to keep a main floor, master, garage bonus room and basement comfortable with less zones.

Less zones will cost you more in the long run. Why wouldn't you want more control and the ability to not have to heat/cool areas you aren't using.

We do not have zones in our home, we were not offered any options and don’t know better at the time, and I fully wish we had them.

Rose,

Based on the information you provided 4 zones would be overkill in my opinion. Things tend to get complicated when trying to control several small zones. Be aware most HVAC installers are not good at planning and installing zones.

The bonus room over the garage would be a good candidate for a zone. The heating and cooling load per square foot is likely very different from the main part of the house. You should not need a zone for the Master bedroom unless you want the room to be much cooler or warmer than the rest of the house. That one comes down to your comfort needs.

If the basement is mostly underground, then the cooling load is close to zero, and the heating load is low. I doubt you will ever be turning on the basement zone for cooling. You might need heating if you want to set the temperature to 75 degrees on a very cold winter night. You could accomplish that with adding duct work from the main house and electric heaters (baseboard or portable) for supplement. This would cost less than installing a dedicated zone. It again comes down to your comfort and convenience.

I think he/she means that it’s very expensive to live in Connecticut

Get a second proposal.

I would suggest dividing the heating & cooling into 2-separate entities, source and distribution. You could have a discussion with a geothermal installer that installs Liquid-To-Water geothermal (source) and then if need be, a separate contractor that installs hydronic (distribution) as in warm and chilled water for the greatest comfort and efficiency in heating and cooling as well as zoning and domestic hot water (DHW).

Anyone discouraging this from a technical point of view would be the wrong professional to be speaking with, from a financial point of view, that’s always your choice.

Get all the information on pros and cons then make up your own mind.

Many who discourage geothermal and hydronic distribution do so because they are clueless on the subject and can’t provide such an installation.

IMPO

SR

What about the other bedrooms? Do they not get to control the temp? I'm not so sure about this. Think it all the way through and definitely speak to the professionals in your area.

Good luck!

Rose,

The zone division really depends on the design and layout of the house. Geothermal will keep your monthly costs down but will greatly increase construction cost over other methods.

A properly installed zoning system, will help you save money and you will see a return in a couple of years. I have 2 zones, I wish I had three. The one missing is for our Master bedroom and bath. We like a cool room for sleeping, but dread that cold bathroom in the morning. If that end of the house had its own thermostat, torture wouldn't be a word in our vocabulary. Probably should have done radiant heat under the bathroom floor....

"Many who discourage geothermal and hydronic distribution do so because they are clueless on the subject and can’t provide such an installation."

No, I suspect because most people don't have unlimited spending budgets and would look at your suggestion as duplicative. Why install two different systems when one can adequately do the jobs needed?

Do you consider all who don't accept your up-selling, needlessly wasteful and expensive suggestions to be clueless?

“What about the other bedrooms? Do they not get to control the temp? I'm not so sure about this. “

If we’re still discussing hydroinics, then with individual adjustable mechanical thermostatic zone valves that don’t even use electricity; cheap, effective, proven technology that’s been around for generations.

Geothermal is not necessarily the end of the world expensive. Whether you install hydronic distribution or forced air distribution with zoning, the installation of the distribution system will be pretty much the same for all forced air whether air-to-air HP, gas, all-electric or geothermal.

The cost of a geothermal HP might not be that much more expensive than a cold climate air-source heat pump and fan coil unit. The difference being the drilling, ground loop and flow centre installation.

One person here is saying geothermal will cost over a million dollars when they mention, “several million” more than a two million dollar build. Another thinks this is “two different systems” when it is but one integrated system installed by different specializing trades.

If you believe that the cost of energy is going to rise, if you believe that the cost of energy going forward might be your biggest HVAC cost - find out for yourself.

You don’t have to believe anyone here.

IMPO

SR

We are builing a new home 2230 sf main floor, 612 sf bonus room over garage, 953 sf finished side basement.

Likely reasoning for the zoning is you've got different areas with much different loads.

Zoning is for the most part already a "cost cutting method" --- because the better way to zone would be to separate the 612 bonus room and 953 sf finished basement from the main home, zone those in some fashion because room over garage will be hotter.

I don't know if what I suggest above would be feasible or not. Doing it that way would likely work better during record breaking heat waves / old man winter episodes.

The 2230 sf main floor would have it's own dedicated equipment. Based on how I read this -- this main floor is all on the same level. I say that because I don't know how you get to the 612 sf bonus room over garage?

Heat rises. Walls of glass / Tall ceilings -- these things look pretty, but they add costs. Either in HVAC expense OR discomfort after you move in.

My suspicion is the builder selling you one piece of equipment then using zoning to accomodate these other areas. On a forum board we lack critical info --- necessary to determine if this will work or not. Comfort means different things to different people which is another dilemma we get involved with here.

If you are under a record breaking heat wave and all zones are calling -- probably not. They are likely planning on that rarely if ever occuring. If it does velocity of air flow will likely give you problems no one is thinking about. For that reason by itself, not a good idea to cut zones.

That same thing can occur in winter. So it's not something to brush under the rug. 3800 SF is alot of area to cover for one HVAC system.

The better way would be to spend more money. Seperate these less used areas from the main floor. You're spending the money for this project so the last thing you'd want is to move in and not be comfortable.

CT's summers aren't that long. If it were me, I would still want to enjoy them in a nice cool house. Plus not worry about when old man winter shows up.

I service the Katy, Texas area. (not a builder - I come after they are long gone)

"Zoning is for the most part already a "cost cutting method" --- because the better way to zone would be to separate the 612 bonus room and 953 sf finished basement from the main home, zone those in some fashion because room over garage will be hotter."

Zoning isn't a cost-cutting method; it adds to the initial cost and maintenance required for any system. Zoning is a means of controlling conditions to maximize occupant comfort, and to a lesser extent, a means of maintaining a healthy indoor environment by reducing the potential for mold and mildew. While some energy savings may be produced by a multi-zone vs. a single-zone system, whether those savings justify the incremental investment in zoning needs to be evaluated on a case-by-case basis.

The mechanical contractor's proposal is for a four-zone system. The contractor is proposing separate zones for the basement and room over the garage and further to subdivide the main portion of the home into two zones. We don't know how those areas are to be zoned. It could be using a single, variable speed air handling unit using thermostatically-controlled dampers or a ductless system with multiple zones of control or some combination of strategies.

Zoning isn't a cost-cutting method; it adds to the initial cost and maintenance required for any system.

Charles read what I said... "for the most part".

Does zoning have other uses... yes.

When you are using it to avoid putting in a second HVAC system --- that is cost cutting.

It is more common to find a zone system in a 2 story home with one HVAC system, than it is to find a 2 story home with 2 HVAC systems AND a zone system.

Does that mean you won't find a zone system in a home with 2 HVAC systems?

Uh, no.

"When you are using it to avoid putting in a second HVAC system --- that is cost cutting."

The need for zoning (the "what") is driven by the climate and the design of the home, the desire for zoning (the "why") is driven by occupant comfort considerations, and the "how" to achieve it is driven by a combination of best design practices balanced by client budget constraints. It's not driven by a need for cost cutting. If you need to cut costs you forgo zoning and deal with the constraints of a non-zoned system.

We find the vast majority of the time it's more economical to install dedicated mini split heat pumps to condition rooms over garages than it is to install a zoning system comprised of thermostatically-controlled dampers. Attempting to zone a basement from a central system using thermostatically-controlled dampers is a fool's errand if there is any need for dehumidification-- and there usually is in heating, mixed and cooling climate zones.

"It is more common to find a zone system in a 2 story home with one HVAC system, than it is to find a 2 story home with 2 HVAC systems AND a zone system."

Be careful generalizing when your experience is limited to a geographic area and homes that go with your typical client demographic, Ray. Ranch homes may be more common than 10-gallon hats in Texas, but here in our (coastal) Virginia area where two-story homes are more common than single-story homes, it is more typical for the home to be conditioned by separate systems for each floor level than it is zoning of a central system.

We find the vast majority of the time it's more economical to install dedicated mini split heat pumps to condition rooms over garages than it is to install a zoning system comprised of thermostatically-controlled dampers.

Economical for whom? A builder that is not coming back once the structure is built?

For every argument there is a counter argument Charles, a house full of mini splits will have much higher costs later so while this is economical for you "the builder" it is not for the home owner in terms of maintenance, repair & eventually replacement.

Noises. It's not uncommon for mini splits to start make clicking noises at some point. You don't get that from zoned systems in my experience. My experience is currently 28 years old in a hot climate.

Be careful generalizing when your experience is limited to a geographic area

Larger builders are nation wide Charles. Just because you don't get out enough doesn't mean others don't. There are vast differences in builds here in my area of Katy, Texas.

The only true difference is we don't have basements here. Two stories / single stories / 3 stories --- if you can imagine it (without the basement) it is done here.

9 ft ceilings, 12 ft ceilings, 15 ft ceilings --- massive grand entrances with 35-40 foot ceilings. large windows 4 ft by 6 foot to small normal windows to walls of glass upwards of 30-40 foot tall.

Charles, you likely only go to homes you have built. I don't get that luxury... I go to homes everyone else has built.

Thousands and thousands of homes over a 28 year HVAC career. All of them unique in their own way.

I never said i was on a budget. I said i was trying to keep cost down. I don't kow why there are a select few answering here who think it's appropriate to talk down. If you don't have a positive comment to share, you can simply just not comment at all. How about just try to be helpful instead of condescending. Verbo Stax

I want to thank everyone else for your positive feedback. I really appreciate it.

Rose I suspect you are new to this forum. Many reply with rude comments almost for sport. Just ignore them as they won’t back down and will never stop.

To reduce any potential humidity problem in your basement, make sure the floor has 10mil plastic vapor barrier underneath It could be required by code. If not add it. Garage too.

The 2018 IRC requires a 6 mil (0.006") polyethylene vapor retarder to be installed beneath basement concrete slabs. Its vapor permeance is less than 0.1. Increasing the thickness to 10 mil doesn't enhance performance in under-slab applications.

Zoned systems are awesome & can focus HVAC on the room(s) most impacted at certain times & seasons. We typically have a zoned 5 ton + a 2nd unit in most 3500-5500 sf homes we've built since 2002.