We are building new in Syracuse NY. About 2000 sqft on the first floor and about 1000 in the basement. My goal is to pick the furnace type based on what would do the best at making the basement comfortable.

I was thinking a 2 zone system so that the basement thermostat would control the basement temperature - at least in winter. The downside to that plan is that my builder is quoting me $4500 for the second zone and since cold air sinks the basement will be colder than the upstairs in the summer time.

What if instead of a second zone we had one zone but it operated more frequently at a lower setting and constantly kept the air moving between the first and second floor? If I could keep that air moving the temps on the two floors would be closer to equal and I could have just one thermostat.

Does that make any sense? And would a 2 stage or modulating furnace accomplish that? And how would I accomplish this same goal in summer time when the AC is operating? Thanks

My questions are based on my experience in my current home. My current home is about 5000 sqft home on 3 levels. The basement and main level are on one zone (thermostat on the main level) and the upstairs is on a second zone. The basement has radiant floor heat with its own thermostat so I guess you could call that a third zone - at least in winter. The house is well insulated and air tight. We run a HRV.

My experience is that the effect of warm air rising and cold air sinking tends to mess with the effect of the multiple zones. In the summer time the upstairs thermostat calls for cooling while the downstairs thermostat does not but because the cold air sinks the basement and first floor stay cooler than the second floor. We tend to get the reverse in the winter time - the first floor thermostat calls for heat more often than the second floor one but the second floor is generally warmer because the heat rises.

Our first floor has a 2 story family room that is wide open to the second floor. And our first floor has a wide open stairway (open railing, no door) to the basement.

My thinking was that the zoning can't really undo those laws of physics (warm air rises, cold air sinks) and that the solution to even temps in the new home might be a system that continuously moves the air and therefore mixes it and negates that rising/sinking effect.

Austin, do you feel that a zoned system that was better designed could overcome those effects? Thanks

If the basement is mostly below ground it will be warmer in the winter when the furnace is not operating. For example if you set back the temperature during the sleeping hours, the basement will stay warmer due to less heat loss. The only time it may be colder is on sunny mild winter days when the house receives heat gain from the sun causing the furnace not to run. Then the basement would be colder but not by much.

I would not install a single stage furnace in a new house especially in a cold climate like Syracuse. You will find the builder's grade equipment is typically single stage. A 2-stage furnace offers more comfortable and a small amount of savings.

Your idea is a compromise. What you could do is install some vents in the basement and a return. Then you would need at least a 2-stage variable speed furnace. The furnace fan could be set to blow continuously on the low speed to constantly mix the first floor and basement air. When the furnace turned on it would heat both floors.

Do you understand what you are getting with the basement zone? Is the furnace being upgraded in addition to the zoning controls and thermostat? You need to post the model details of the two options in order to see if $4500 is a fair price. Upgrade options are usually big profit items for builders. You have to decide whether spending the extra money is worth it.

A finished well insulated basement does not take much to keep warm. You could just add a few vents in the basement and then have supplemental electric baseboard heat, or portable radiant heaters. Heating with resistance heat can get expensive. However it may only take 10K BTUs to keep the basement warm. That is the heat provided by two 1600W heaters. It may not be expensive to operate if you use the basement infrequently in the winter. In the summer you will require no additional cooling.

"A 2-stage furnace offers more comfortable and a small amount of savings."

Can you talk about how a 2 stage furnace operates? When does it use each of the stages?

"Then you would need at least a 2-stage variable speed furnace. The furnace fan could be set to blow continuously on the low speed to constantly mix the first floor and basement air. When the furnace turned on it would heat both floors."

I think that's what I would like to do. Is this something that any HVAC sub will know how to do? The basement is for my college age kids who will be home for a month in the winter and 3 months in the summer. Is this set up the sort of thing that I can change based on whether the basement would be in use? Have you ever heard of anybody setting up a furnace fan to run continuously like that?

"Do you understand what you are getting with the basement zone? Is the furnace being upgraded in addition to the zoning controls and thermostat?"

I have no idea. Have not had detailed discussions with the builder on this. He just threw the $4500 number out there and I recoiled in horror.

"You could just add a few vents in the basement and then have supplemental electric baseboard heat, or portable radiant heaters."

That's what me and the builder proposed ... wife vetoed that idea.

A 2-stage (some furnaces have multiple stages) can operate in either the low stage or high stage. In the low stage the burner has a smaller flame and the blower fan runs slower. In the high stage both the burner and and fan run at maximum. When installed correctly, the staging is done by the thermostat. When there is a call for heat the thermostat will usually start in the low stage and then go into the high stage if the temperature in the room can't be reached in a set amount of time. It then will go down to low stage and then finally shut down when the temperature is reached.

A good HVAC contractor should know how to install multiple stage equipment. Unfortunately builders hire the cheapest installers who many not a good job. You need to ask a lot of questions. You can always change the fan to run continuously or only when the furnace is operating. My furnace is a Carrier Infinity 3-stage with the ability to run the fan continuously in low, medium, and high as well as auto.

If you only need to keep the basement warm when the kids are home from school on winter break, then I don't see the need to spend a lot of extra money. Add some extra vents in the basement with a manual damper that can be closed when not needed. The cost of running the space heaters will never approach $4500.

Quote: My experience is that the effect of warm air rising and cold air sinking tends to mess with the effect of the multiple zones. In the summer time the upstairs thermostat calls for cooling while the downstairs thermostat does not but because the cold air sinks the basement and first floor stay cooler than the second floor. End Quote.

It will to one degree or another, however a zone system is designed to 'minimize' this problem by controls that direct the cooling or heating to where you want it.

Naturally the upper levels of the home will call for cooling more frequently than lower levels. Zoning isn't entirely perfect, in many cases it depends on the home layout. If you have a home that is more 'open' you will get bleed thru from one zone to another. But what difference does it make if you have better control? Assuming of course the zone system is installed properly... many times they are not.

The best control of a zone is a zone in which there are 4 walls and a door and preferably there is a return as well as supply duct(s) within that zone. On a multiple level home that is zoned the equation changes some what in that each level of the home is typically a zone.

Sure the bottom levels of the home will be cooler than the top level (second floor). The idea in zoning the AC to the basement is to 'limit' the amount of cooling it receives... otherwise the complaint is always the 1st level is too warm and the basement is too cool.

Zoning is merely to give you better control and reduce complaints.

The other thing that you may not realize is that zoning has the capability to cool one area while heating another area. Not at the same time of course with one HVAC system, but it can vary the cycles. It's all about comfort and control when it comes to zoning. (Think of a yuppie 3 level home with only 1 HVAC system.) Without zoning can you imagine the fights of the lower level of a 3 story home with 1 HVAC system in fall and spring seasons with someone who is on the 3rd level?

Savings can be achieved by only cooling or heating areas of the home that need it.

A couple of people have referenced "proper installation" of a zoned system. What are the ways that it should or shouldn't be done? As I said, the lower zone will be a finished basement and the upper zone will be the above ground floor of a one story home. There will be no door between the two levels.

Thanks for all the useful replies.

Experience in sizing, zoning controls, ductwork, and the HVAC itself...Carrier has the best integrated zoning system in the residential market...qualify the dealer's experience in this area...visit jobs that the dealer has installed...

IMO

You will get more efficiency and a less drastic temperature swing with a two stage furnace. As long as the price difference isn't drastic it's a pretty good idea. As far as modulating different manufacturers call "modulating" different things. Two stage is good, but a true modulating furnace with a true ECM motor can get pricey on installation and really pricey if repairs are needed. I have written an article on different kinds of furnaces and the pros and cons. If you're interested, you can see it HERE. By the way, if your fuel is natural gas, the differences are less critical, but if you are using LP, efficiency then becomes a huge issue as the cost of LP is significantly higher than natural gas.

That link brought me to your web site and I registered but was not able to find the article you are referring to. Can you point me to it? Incidentally I was just in your neighborhood - flew in and out of Memphis on my way to dropping my son off at Ole Miss. Thanks

A couple of people have referenced "proper installation" of a zoned system. What are the ways that it should or shouldn't be done?

Every home is different. Different strokes for different folks. Then location of the property may pose challenges during extremes of seasons.

If the location is hot all the time poses unique challenges.

If the location is hot & humid all the time poses unique challenges.

If the location is a colder climate poses unique challenges.

'Proper Installation' - refers to the goals of the job. Each one is unique to one degree or another. You must realize there will be times when only one zone is calling for heat or cooling either one. If the zone system can't handle this equation during shoulder seasons as well as extremes of the climate it simply will not work. It can lead to premature failure of the equipment not to mention blown apart duct work and or failure of the zone system controls etc.

quote: Carrier has the best integrated zoning system in the residential market.

No two dealers are alike it is pointless speculation to refer to branding as in something that is 'deemed better'--- Carrier Manufacturing doesn't make house calls - They will refer you to someone like me. Integrated means 'proprietary controls' in most cases this is only going to lock you into higher repair costs. If the installation is done improperly brand of zone controls make very little difference. Obviously there are very cheap products in the realm of zoning controls. So you want a HVAC Contractor well versed in such systems.

"Ha, ha, ha... that is like comparing a Toyota to a Lincoln or Cadillac."

Are you familiar with Carrier's zoning system with the fully modulating dampers, communicating zone controllers, and sensors? The one which can control up to 8 zones? That's what you can buy from a Carrier dealer if you have a large house and want the temperature in every room to be consistent as possible. It is the Cadillac of zoning systems.

Yes you are correct if your Carrier dealer doesn't know how to install it properly, Carrier Corporation will not fix it for you. That's why proper installation is important.

If on the other hand you have a simple two zone system, you can buy the generic damper control that open and close. Those can be connected to any brand of equipment. That would be more of the Toyota class of equipment.

Well mike_home,

Carrier is not the only manufacturer to make communicating zone controllers, sensors etc.

There is a multitude of zone control manufacturer's and a lot of it is junk to one degree or another.

PS... 8 zones in a residential setting would be over kill.

Well if there are other brands that have communicating zone controllers then share that information. The OP may not have a good Carrier dealer in his area and may need to work with someone else. Also if you believe in your professional opinion the other brands of zoning controls are better in terms of features, programming, ease of installation, and long term reliability then share that information also. The OP has been quoted $4500 to add zoning for his basement. He does not know what type of zoning he is getting. He also is not knowledgeable about the spectrum of zoning options available some of which could be brand specific. Providing information about it would be helpful.

It is interesting to hear you say that some the zoning controls of some brands are junk to one degree or another. I take it you believe that brand does matter when it comes to zoning equipment.

I do agree 8 zones is over kill. I would recommend getting 2 or maybe even 3 separate systems before installing 8 zones. The point I was making is Carrier offers a zoning product that has many features, so one could argue it is best in class in that regard. I am not a zoning expert There could be even better options available. I don't know who makes them.

I think the Carrier system can modulate up to 8 dampers. I could imagine a zoning system where more than one damper is used for each zone. For example when one only one zone is calling for heat in a 5 ton system, a bypass may have to be opened in order to balance the air flow. I could see the zoning design can get quite complex and likely to be beyond the capability of a typical HVAC installer and repairman. This is why the homeowner needs to really scrutinize the capability of the installer before he hires them to install a zoning system.

@ mike_home:

Well if there are other brands that have communicating zone controllers then share that information.

Air Conditioning and Heating is an 'extremely competitive market'. My competition would 'love' to understand and know better what I do.

All brands of zoning products make junk, just as much as they make better products. Just stating one brand isn't helping when installation of such systems can be quite complex, not to mention challenging.

It is common knowledge that DIY's exist on this board as well as others. This is a conflict of interest. I have no desire to be called to a zone system with problems that wasn't professionally installed.

I offer a service in which I come to your home to determine if zoning is feasible or not. Zoning is not a cookie cutter type solution. If it cannot be done properly it's of no use to mention brands of various products.