New Home HVAC System

[Sigarms]

The night we hit -21 I checked my usage on the units. From midnight to 8 am each unit ran just over 7 hours so they ran almost non-stop but maintained a 73 degree setpoint in all zones.

Just curious why 73 on all zones unless that's what you've got to work with per the duct layout? I would just think that the unoccupied space when zoned would be set higher or lower on the t-stat depending out outside air conditions.

Because the dogs are on our first floor, keep it at 64 between at night and early morning during winter. Third floor is generally 68 at night (in winter) while the basement is no lower than 74. I did install a whole house dehumidifier for the home that allows me to run a higher than normal t-stat setting in the summer (generally around 77F on the first floor), but that draws a good amount of power as well and offsets the higher t-stat setting in the summer, but the wife loves the comfort.

Note - one advantage of a multi zone mini split when in heating or cooling mode. You can maintain individual zone temps for each room. You can't however have one zone call for heat and another call for cooling. That's the advantage of commercial VRF ductless systems.

 

[jk96]

Just curious why 73 on all zones unless that's what you've got to work with per the duct layout? I would just think that the unoccupied space when zoned would be set higher or lower on the t-stat depending out outside air conditions.

Because the dogs are on our first floor, keep it at 64 between at night and early morning during winter. Third floor is generally 68 at night (in winter) while the basement is no lower than 74. I did install a whole house dehumidifier for the home that allows me to run a higher than normal t-stat setting in the summer (generally around 77F on the first floor), but that draws a good amount of power as well and offsets the higher t-stat setting in the summer, but the wife loves the comfort.

Note - one advantage of a multi zone mini split when in heating or cooling mode. You can maintain individual zone temps for each room. You can't however have one zone call for heat and another call for cooling. That's the advantage of commercial VRF ductless systems.

I used 73 as I was too lazy to type it all out and this is our main living space. Zones: Living room - 73, Dining/kitchen/laundry - 71, Master - 70, Upstairs left - 71, Upstairs right - 71, Basement - 69 Basement rarely calls for heat at that temp and maintains close to that in the summer without cooling so there's around 900 sq/ft that doesn't require much. Main living room is vaulted across the entire center of home so the upstairs zones get less calls in winter as well.

 

[lman]

To ensure we're on the same page, what are you proposing for residential use for home heating and cooling, not commercial use?

To some extent, why Geothermal is one of the best sources for HVAC for residential use, but also more expensive than forced air.

My geothermal is forced air. My strip heaters have never run as they have been disabled. It was -20 a couple years ago, -10 a couple days ago. Confused what you're trying to say.
My geothermal can't be more expensive than forced air because it is forced air.

 

[jk96]

My geothermal is forced air. My strip heaters have never run as they have been disabled. It was -20 a couple years ago, -10 a couple days ago. Confused what you're trying to say.
My geothermal can't be more expensive than forced air because it is forced air.

I think he's referring to a standard forced air setup vs geothermal water to air.

 

[Sigarms]

My geothermal is forced air. My strip heaters have never run as they have been disabled. It was -20 a couple years ago, -10 a couple days ago. Confused what you're trying to say.
My geothermal can't be more expensive than forced air because it is forced air.

I should of stated "air to air", apoliges for the incorrect terminology. When I say "forced air", I meant air to air source but did not specify that.

Yes, geo units have a blower to move the air just like a standard heat pump air handler, thus it's "forcing" the air to move.

That's why when someone says "VRF" vs "ductless mini split", there is a difference IMO. I actually do more inverter mini splits and VRF for commercial than Geothermal in my area. Federal tax credits going away in NC kind of killed the geo market in my area, and the local utility companies don't offer much bigger rebates with water source vs air to air systems.

 

[Sigarms]

I used 73 as I was too lazy to type it all out and this is our main living space. Zones: Living room - 73, Dining/kitchen/laundry - 71, Master - 70, Upstairs left - 71, Upstairs right - 71, Basement - 69 Basement rarely calls for heat at that temp and maintains close to that in the summer without cooling so there's around 900 sq/ft that doesn't require much. Main living room is vaulted across the entire center of home so the upstairs zones get less calls in winter as well.

When you parents move into your basment, the heating will be set higher than anywhere else in the house. Just a heads up LOL

 

[jk96]

When you parents move into your basment, the heating will be set higher than anywhere else in the house. Just a heads up LOL

I have no doubt. Dad's house about cooks us when visiting and still uses an electric blanket.

 

[RalphVa]

We are in the planning stages of building a new house. My original thought was to have a standard central air and heat ducted system using heat pump with propane backup. We also will have non vented fireplace with gas logs for supplemental or backup heat if the power goes out.

In talking to a friend who retired from the HVAC world he suggested looking at a Mitsubishi Multi Zone Mini Split System. Multi-Zone Cooling and Heating Outdoor Units | Mitsubishi Electric

Are any of you guys using a system like this in your house or have any knowledge of it? I have studied it some and it certainly looks interesting. I like the idea of each room/area temperature being controlled independently. I also like the idea of no duct work as well.

I'd go with the ductless ones. Ours is Fujitsu. They're more efficient than the ducted units. However, our newest (2 ton) ducted unit for the upstairs runs without having the backup electric coil. We've it shut down via thermostat. Cannot have the coil available if on backup generator. Ductless do not use any coil backup.

Ralph

 

[RalphVa]

Goethermal would be even more efficient than dustless. If you have space to lay the underground lines for it or can put in a separate well for it, it's the way to go. We don't have the space for it here.

Ralph

 

[Sigarms]

I have no doubt. Dad's house about cooks us when visiting and still uses an electric blanket.

LOL My dad uses an elctric blanket as well when he's sitting on the couch watching TV and it's it's still 75-77F down there.

To put an oil boiler into perspective for heating, at his old house, he never put the T87 tstat past 72. Can't beat radiant heat for the warm feeling.