New Home HVAC System

[truckdiagnostics]

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.

i believe we are on the same page. The point i am trying to make is today, you do not necessarily want a ductless system, as you want to exchange the inside air with the outside air. You can do it with a HRV, then you are looking at ducts and you might as well have used a simple air handler with ducts. Commercial buildings are going to demand so many air exchanges an hour. i would think you would want something similar in a new home. In the future slapping a mini split on the wall and not exchanging the air isn't going to get it. For a single server room or simple one room addition as a band aid, yes. So, yes a residential house with a geo unit heat and chilling water would get it. I do believe a vrf would get it too. I am not that familiar. Then you fish pex water line through. Use horizonal chilled case coils and basically you have one unit and some pumps. I believe you can get the VRF to the same thing, but it is more complicated.
When the outlaw's come for thanksgiving and one of them has the flu I don't want them giving it to everybody.
You brought up office building. Those same unit that they are using as ground source heat pumps they are using to take the heat out of the air before it leaves the building(air source). Converting it to hot water, then using it to heat the air going into a particular room. This way they can move the heating and cooling around. Say every one in the office just moved into the conference room. Well you wouldn't need to heat the air going in there anymore. That zone would shut off and you would divert the hot water to the office area.
So, how much more is geo(ground source) really than forced air gas heat once you throw in AC? Basically it is the cost of the ground source loop. If you include that it can heat your potable hot water?

 

[jk96]

Can't beat radiant heat for the warm feeling.

Agreed. Everyone in the house loves the fireplace. Only prob for me is staying awake. The radiant heat plus blower noise and I may as well have taken a sleeping pill.

 

[Sigarms]

i believe we are on the same page. The point i am trying to make is today, you do not necessarily want a ductless system, as you want to exchange the inside air with the outside air. You can do it with a HRV, then you are looking at ducts and you might as well have used a simple air handler with ducts. Commercial buildings are going to demand so many air exchanges an hour. i would think you would want something similar in a new home. In the future slapping a mini split on the wall and not exchanging the air isn't going to get it. For a single server room or simple one room addition as a band aid, yes. So, yes a residential house with a geo unit heat and chilling water would get it. I do believe a vrf would get it too. I am not that familiar. Then you fish pex water line through. Use horizonal chilled case coils and basically you have one unit and some pumps. I believe you can get the VRF to the same thing, but it is more complicated.
When the outlaw's come for thanksgiving and one of them has the flu I don't want them giving it to everybody.
You brought up office building. Those same unit that they are using as ground source heat pumps they are using to take the heat out of the air before it leaves the building(air source). Converting it to hot water, then using it to heat the air going into a particular room. This way they can move the heating and cooling around. Say every one in the office just moved into the conference room. Well you wouldn't need to heat the air going in there anymore. That zone would shut off and you would divert the hot water to the office area.
So, how much more is geo(ground source) really than forced air gas heat once you throw in AC? Basically it is the cost of the ground source loop. If you include that it can heat your potable hot water?

We are on the same page.

The issue is do you realize how many new homes (built now) bring in outside air via a system designed for that process? It's not high in at least my area. No one wants to spend the money.

Bring in outside air at 40F with low humidity for cooling, no problem. Bring in outside are at 90F with high humidity for cooling, you may have a problem.

Have a 20 ton gas pack or heat pump with economizer, no issue with outside air. Thing is, people don't want to spend the money they need for a HRV/ERV for residential use.

The biggest issue with water source for residential use is loop layout and construction for loop vs air to air. Generally speaking, water source (geo) will run 2 to 3 times more than air to air for that fact alone. Reality is you still need ductwork for both water source and air to air.

As far as ductless, I'm a huge proponent of it, given the right application. Doing a whole home with ductless I'm not a fan of for numerous reasons. Thing is, marketing for ductless manufacturers will try to convince you otherwise.

You have a one story house running on a LP gas furnace with one t-stat in the living room or hallway, with only the owners sleeping at night in a master bedroom? Spend the money on a ductless mini split and you'll see a ROI within 1-3 years depending on price of LP in that area (where heating exceeds cooling load).

 

[jk96]

We are on the same page.

The issue is do you realize how many new homes (built now) bring in outside air via a system designed for that process? It's not high in at least my area. No one wants to spend the money.

Bring in outside air at 40F with low humidity for cooling, no problem. Bring in outside are at 90F with high humidity for cooling, you may have a problem.

Have a 20 ton gas pack or heat pump with economizer, no issue with outside air. Thing is, people don't want to spend the money they need for a HRV/ERV for residential use.

Build tight and ventilate. Seems to be a foreign concept in my area as well. We added the HRV after the fact. I specifically asked our HVAC about the need for one. His response was no due to the volume of home, lots of doors/windows, and an active house with 5 people living there we did not need one and would have plenty of outside air movement. After moving in I started monitoring CO2 levels and we were hitting 1200-1300. Our HVAC guy seemed shocked when I called back to add it. I have it set to run 20 minutes an hour and levels stay around the 620-650 mark. If you stand outside the out-take and smell what is being pumped out of the house you would be a quick believer. Amazing how un-fresh the exhaust air is.

 

[truckdiagnostics]

Build tight and ventilate. Seems to be a foreign concept in my area as well. We added the HRV after the fact. I specifically asked our HVAC about the need for one. His response was no due to the volume of home, lots of doors/windows, and an active house with 5 people living there we did not need one and would have plenty of outside air movement. After moving in I started monitoring CO2 levels and we were hitting 1200-1300. Our HVAC guy seemed shocked when I called back to add it. I have it set to run 20 minutes an hour and levels stay around the 620-650 mark. If you stand outside the out-take and smell what is being pumped out of the house you would be a quick believer. Amazing how un-fresh the exhaust air is.

Yup, then there is the moisture mold issue without one. Build a tight insulated house then poke a hole in it. New Homes if it isn't it will be code. Exchanging the air in the summer gets tricky, cause it brings in a bunch of moisture, then you drive up the humidity level in the house wife turns down the temp because she is having a hot flash, ugh. Then you end up with a humid coldness in the house. I ended up having to add a whole hose dehumidifier. Brought down the humidity in the summer. You bring that humidity down to 40-45% in the summer you can bring the indoor temp up. Works slick should have done it a long time ago.

 

[Sigarms]

Build tight and ventilate. Seems to be a foreign concept in my area as well. We added the HRV after the fact. I specifically asked our HVAC about the need for one. His response was no due to the volume of home, lots of doors/windows, and an active house with 5 people living there we did not need one and would have plenty of outside air movement. After moving in I started monitoring CO2 levels and we were hitting 1200-1300. Our HVAC guy seemed shocked when I called back to add it. I have it set to run 20 minutes an hour and levels stay around the 620-650 mark. If you stand outside the out-take and smell what is being pumped out of the house you would be a quick believer. Amazing how un-fresh the exhaust air is.

One thing about HVAC doing it for a while, no one is an expert on everything.

Didn't know anything about heat pumps until I moved south. Up north, a package unit only goes on a roof. If a guy tells me he's an "expert" in both oil and heat pumps, he's either one of the smartest guys I ever met in my life or he's pulling my leg.

It's apparent your house has a very tight envelope. I'm guessing the owner of your HVAC company who did your work was in his 50's or 60's (or even older), very hands on, but wasn't used to dealing with a ultra tight sealed home with insulation to the max.

The reality is your house is the exception, not the norm.

There is a old school thought that a house should be able to breathe. One thing I know is if it's what a homeowner wants, you give them the pros and cons in your professional opinion if you think they are spending more than they need to, but if they still want it, you give it to them (without hurting the system being installed). Some homeowners think bigger is always better, but that line of thinking can also hurt you, and as a business owner, you need to protect yourself in the proposal).

 

[Sigarms]

Yup, then there is the moisture mold issue without one. Build a tight insulated house then poke a hole in it. New Homes if it isn't it will be code. Exchanging the air in the summer gets tricky, cause it brings in a bunch of moisture, then you drive up the humidity level in the house wife turns down the temp because she is having a hot flash, ugh. Then you end up with a humid coldness in the house. I ended up having to add a whole hose dehumidifier. Brought down the humidity in the summer. You bring that humidity down to 40-45% in the summer you can bring the indoor temp up. Works slick should have done it a long time ago.

The way guys are getting around code in new homes for cookie cutter projects is bringing fresh air through the "fart fan" in the bathoom. Minimal cost.

 

[jk96]

It's apparent your house has a very tight envelope. I'm guessing the owner of your HVAC company who did your work was in his 50's or 60's (or even older), very hands on, but wasn't used to dealing with a ultra tight sealed home with insulation to the max.

The reality is your house is the exception, not the norm.

Early 50's. I had the benefit of being my own general contractor so I was here almost every day of the build checking on the subs I hired or was doing some of the work myself. Because of that I had the time to work on air sealing that would not have been practical for a turn-key builder. If there was a gap between two studs that would hold foam or caulk it was sealed up. Spent several days with a borrowed blower door and smoke finding and sealing leaks.

 

[Steppenwolfe]

One thing about HVAC doing it for a while, no one is an expert on everything.

And this is what makes it so hard to know who is "right". My hardest problem as a GC is choosing the right sub to do the job. Even with a set of blue prints from an engineer I have to wade through bids to make sure everyone is bidding the job correctly; and you would be surprised how many don't. It all comes down to your gut feeling and trust in the end.

 

[Rustyiron]

Sig, thanks for your contribution here.:thumbsup: