[Greenlight1]

What is the “best” choice now a days for installing the highest efficiency heating system? Our remodel is underway and we are almost at the point of choosing a heating system. Home is around 3500sq ft (including basement which is a walk out with approx 60% above grade) The structure is fully gutted so we can do anything we want. I am planning on have R-60 in attic and R-25 on all exterior walls. Also planning to add ISOboard to the exterior walls to decrease any thermal bridging. The home will also be sealed to have about 1ACH (including basement).
Side note, our Electrical company is owned by our township so our rates are a lot higher than normal (12.450 cents per KWH)
I would like to do a hot water in floor system throughout the house and really do not see a downside to that type of system except the initial cost for running all the lines.

 

[yuri]

Hot water is VERY comfortable and you don't get drafts and cold spots.

However if you need AC then you need a attic airhandler and the cost overall goes up.

If you make your house very airtight you may need a ventilation system like a HRV/heat recovery ventilator or ERV in warmer areas. That needs to be ducted in.

Lifebreath is the best brand for them IMO.

https://www.lifebreath.com/products/residential-heat-recovery-ventilation-hrv-units/

 

[user_12345a]

You can achieve similar comfort to hot water with a modulating furnace.

Problem is modulating furnaces may not come small enough for a high performance home to see the full benefit.

They start at 60k btu in most brands (66k for lennox) and believe it or not homes with very good construction may only required 40k btu input.

Regardless of what heating system type you get, make sure an accurate room by room load calculation is done and your contractor doesn't blindly upsize out of fear of complaints.

Most comfort problems are caused by a combo of bad distribution system and too large equipment. Hot water though is far less affected by both than forced air.

Less efficient homes* of the same size (home is probably more like 2500 sq ft plus basement - basements have low heat loss) would typically get a 60 to 80k 95%+ furnace in most moderate climates that get real winters.

*Like R11 walls, 3-5 ach @ 50 pa blower door, R30 attic.

If you end up with radiant heat but want a/c, can look at mini-splits.

For central, whatever you do, don't put any a/c ducts outside of the thermal envelope.

 

[roughneck]

What fuels are readily available? Natural gas?

 

[Greenlight1]

You can achieve similar comfort to hot water with a modulating furnace.

Problem is modulating furnaces may not come small enough for a high performance home to see the full benefit.

They start at 60k btu in most brands (66k for lennox) and believe it or not homes with very good construction may only required 40k btu input.

Regardless of what heating system type you get, make sure an accurate room by room load calculation is done and your contractor doesn't blindly upsize out of fear of complaints.

Most comfort problems are caused by a combo of bad distribution system and too large equipment. Hot water though is far less affected by both than forced air.

Less efficient homes* of the same size (home is probably more like 2500 sq ft plus basement - basements have low heat loss) would typically get a 60 to 80k 95%+ furnace in most moderate climates that get real winters.

*Like R11 walls, 3-5 ach @ 50 pa blower door, R30 attic.

If you end up with radiant heat but want a/c, can look at mini-splits.

For central, whatever you do, don't put any a/c ducts outside of the thermal envelope.

Thank you for the info. AC is not a huge deal for us in terms of design of system. I agree, mini split will be the ticket, if we decide that we want to do AC. I am going to have an engineer come out from our plumbing supply house and do a manual J for me and I am going to be installing almost all the system by myself, aside from boiler hook ups and gas lines.

 

[Greenlight1]

What fuels are readily available? Natural gas?

We currently have an oil fired Boiler but we have had gas lines run to the house so Natural gas is going to be our fuel of choice.

 

[Greenlight1]

Hot water is VERY comfortable and you don't get drafts and cold spots.

However if you need AC then you need a attic airhandler and the cost overall goes up.

If you make your house very airtight you may need a ventilation system like a HRV/heat recovery ventilator or ERV in warmer areas. That needs to be ducted in.

Lifebreath is the best brand for them IMO.

https://www.lifebreath.com/products/residential-heat-recovery-ventilation-hrv-units/

I agree 100% with the tightness being an issue. We ran our ASHRAE calculation and are going to need mechanical ventilation. HRV’s seem a little more feasible in our climate, Northern Pennsylvania. This is something that can be installed anywhere throughout the home, correct? We will not have any ductwork (hopefully) so it can’t be tied into that. We have also used ASHRAE compliant Exhaust vents in bathrooms that are controlled by “smart” switches that can be set to run X minutes per hour.

 

[Bud9051]

Just a comment for you. I'm doing a deep energy retrofit of my cape here in Maine and improvements so far are impressive. The old set back thermostat days are long gone as the house just stays comfortable all the time. Once the comfort issues level off further improvements will only be seen in the cost of energy and basically that can make it difficult to spend more, the ROI becomes very long term.

Include a back up system if your area loses power at times.

As user said, not too big of a system. Also, don't know what your humidity does in summer but an ac unit is your dehumidifier.

Enjoy
Bud

 

[yuri]

Where I am most new homes use a HRV for the bathroom exhausts plus have a couple intakes in the house for ventilation.

That way we don't have to penetrate the roof or outer walls with bathroom exhaust fans.

You can have a dedicated HRV system and do the bathrooms or just the house.

Read the install manuals for some of the Lifebreath HRVs and they explain the different types of setups.

I have a 155 Max

https://www.lifebreath.com/product/lifebreath-155-max-residential-heat-recovery-ventilator-hrv/

https://www.lifebreath.com/wp-content/uploads/2019/10/69-MAX-Install-10-19.pdf?x39965

 

[user_12345a]

You absolutely can have a dedicated duct system for an HRV.

Easiest install location is near an exterior wall - ideally in same room as boiler.

----------
A detail i forget to provide:

For hot water heat, to get best efficiency the return water temperature has to be as low as possible. If the system design will require the boiler outlet is 160 to 180 insist on an outdoor reset.

I'm sure the fancier boilers have outdoor reset built in.

 

[beenthere]

1 ACH is a fairly loose house. No mechanical ventilation needed.

Now if it was less than .2 ACH you would need mechanical ventilation added.

 

[Greenlight1]

1 ACH is a fairly loose house. No mechanical ventilation needed.

Now if it was less than .2 ACH you would need mechanical ventilation added.

I’m not sure if I understand how you came up with that. When we used the Red Calc software, it told us even with a rate of 4.0 ACH additional ventilation would be required. Is that 4 Air Changes Per Hour? Or is 0.4 considered 4 exchanges per hour?

 

[Bud9051]

Hi Greenlight, just following along. Getting old in my retirement but I think you are correct. Assuming your 1 ACH is actually 1 ACH50, that would be getting close to Passive House numbers, but what they use now I haven't followed. Here's some reading.
https://www.greenbuildingadvisor.com/article/time-move-away-ach-50-pascals

Back to the pros and I will do more reading myself.
Bud

 

[Greenlight1]

Hi Greenlight, just following along. Getting old in my retirement but I think you are correct. Assuming your 1 ACH is actually 1 ACH50, that would be getting close to Passive House numbers, but what they use now I haven't followed. Here's some reading.
https://www.greenbuildingadvisor.com/article/time-move-away-ach-50-pascals

Back to the pros and I will do more reading myself.
Bud

You had me rechecking all the number I got LOL!!! I do appreciate any input I get from anyone though so thank you. I am BPI certified for blower door and ASHRAE calcs but when you are designing a home it is a whole different ball game that I do not have any experience in. I’m hoping all the extra work and time will be worth it to enjoy low heating bills and a comfortable home year round

 

[Bud9051]

I was also BPI but gave up chasing their certification when I slowed down. I got into energy auditing because I wanted to help people save energy then along came gov programs that needed to verify the amount saved, thus the certifications, PITA. I'll avoid my rant.

But doing my own deep energy retrofit has been a learning process, 79 cape. I too hope to make heating costs a miscellaneous expense. I have audited some very good homes and the results of doing things right when built are impressive.

Best,
Bud

 

[user_12345a]

I assumed you were referring to ACH result of a blower door test, not natural leakage.

ACH - natural at best is a guess, n-factors don't necessarily reflect what happens in the real world.

 

[coolair111]

If you are going to remodel then you should also consider ductless heat pump. These are customizable and unlike natural gas the carbon foot print will be a lot less. The smart ductless systems are getting quite popular because of efficiency and energy savings.

 

[yuri]

The carbon footprint is a misnomer IMO.

If you have to burn coal or fuel in a power plant to produce the electricity for the heat pump then the result is the same.

Hydro electric power has drawbacks too as the dams leach mercury into our land and that is a issue. However we have LOTS of rivers and hydro power in Manitoba so we use them anyway.

There will not be enough solar power etc for a long time to take enough of the load away from power plants to reduce the number of them but every bit helps. I would not make a decision to use them because of that idea though.

IMO ductless units are OK for special applications but they can be very difficult to gets parts and tech support for unlike a conventional furnace or boiler. They are kind of in the throwaway category and especially with the cheap Chineez knockoffs.

If you buy a high end Fujitsu it will last longer but they are quite expensive but worth it.