Heating systems for new home
 

After learning more about how efficient mini splits are I’m reconsidering them for a new house.

The new house is gonna be on a 4 ft crawl space, due to ledge.

I was leaning towards a forced hot air system with a heat pump (heat and cool)

Probably a direct vented propane stove for back up.

Some pro’s and con’s of each:

The forced hot air system:
would cost a lot more. Probably double or more.
Would turn the 4ft crawl space into a 3ft crawl space for duct work.
Would allow integrated humidifier
Would allow integrated air quality control (fresh air intake)
Not sure how close to a mini split efficiency you can get.

Mini Split:
Super efficient
Probably easier to control “zones”
No way to humidify with them.
No way to manage fresh air (that I know of)
Kinda ugly wall units.
Ever so slight fan noise.
Need to get plumbing to each head unit.

You have to be careful with tight energy efficient homes these days with indoor air quality. Need to pimp in sone fresh air. I could put an independent system.

The new house will be a post and beam an I would like to manage humidity some in winter to minimize to much beam checking. And health wise. I’ve not had the best luck with central humidifier systems. Assuming they have better stuff these days. Lots of issues with these. Types that make steam are expensive to run. Cool mist type systems are prone to mold.

I also plan to add Solar. And I think we have ruled out geothermal (which is basically a heat pump).

Any thoughts on this topic.

I have mini splits in Mass. We love them for their room by room control, efficiency, low maintenance, and quiet. A couple of thoughts based on your post:

Agree they do not look as good, but after you live with them, they tend to disappear.

If you would like fresh air, I recommend an energy return ventilator. This is a separate system that pulls air from outside in an energy-efficient manner.

Do you mean humidifier or dehumidifier? I've never thought of humidifying a home

I'm curious why you ruled out geothermal...other than possibly cost. We installed geothermal in our newly built CT home 26 years ago and couldn't be happier with it. A good percent of our system was subsidized by CL&P (now Eversource) credits but I'm guessing such benefits aren't as lucrative these days as they once were.

Humidifier. Beam checking occurs when the wood dries out... generally during low humidity winter. Farmers used to keep a kettle on the wood stove, and a kettle of soup simmering.

mini splits ARE NOT super efficent in the winter. if you get the Mitsubishi with the hyper heat they are not "super efficent in the winter" and they should not be considered your primary heat source. we do alot of remodeling.

Have not heard "not super efficient" before. Our mini splits are virtually our only hear source in Mass, and they've done extremely well even on extremely cold days, like 5 or 10 below in the record cold of 2-3 years ago. Super cheap to run too--comparisons are tricky, but I think less than half the cost of oil.

We have Mitsubishi, I don't think our model has "hyper heat"

My son-in-law installs Mitsubishi mini splits for a large company in northeastern MA. He is constantly advising people that they should not rely on the mini split as their only heat source, even the hyper heat units. Regarding efficiency - as it gets colder the efficiency drops.


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I’d go with the forced hot air all day long and run the ac thru that. If u do the mini splits up here you definitely need the hyper heat heat. Cost wise I’m not sold on them and I don’t like the look of them.

I have central air with a forced air system and have been in homes with mini-splits. My home's temps are consistent— ±.5° —but those with mini-splits I've been around tend to have cool areas, especially when working and anywhere near seating, etc.

I also much prefer the simplicity of one return filter, one unit, one set of controls, etc.

That being said, I don't love forced air heat—I much prefer baseboard or forced hot water for its evenness—but both systems would be air, so I'd still choose the central system.

I've not looked in a while, but I've gotta think the new heat pump furnaces are super efficient?

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Condensing furnace
 

The mini-splits are great in the summer. Highly recommended for cooling and mild weather heating but as stated above, not efficient for cold weather.

As for winter use, a condensing furnace is your best bet if you plan on forced air. I personally prefer radiant heating. I also prefer the ones with on-demand hot water for even more efficiency!

Mitsubishi Hyper Heat
 

We built a small house last year with a 3-ton Mitsubishi Hyper Heat Pump and ducted air handler that provides heat and AC. There is a backup resistive heat strip that turns on below 5 degrees. The ducts provide air to every room. It works very well for us. The new house is very well insulated, and it’s important to do a good job insulating the duct work. We aren’t at the house much in the winter, and the highest electric bill was less than $200.

Heating system for new home
 

With the exception of a wood-burning stove, just about all other forms of heating systems rely on electricity, and to that end, I would suggest that you include a whole-house generator in your heating plans. At the time of original construction the cost of including a whole-house generator is reasonable. If you wait, and do it as an after-construction addition, the cost will be much more.

A whole-house generator should also be considered if you are on your own well and on your own septic system.

Still not sure what folks mean by not efficient in cold weather. My mini splits are super low cost to operate in total, and I'm always warm. Since I'm warm every day, and paying low monthly bills, I'm not sure why I should care if they are less efficient on some days?

For a new house, your first thought should be to make it superinsulated and very tight. The cost to do this is relatively little extra, and the savings in heating/cooling costs pays for the extra cost in little time. The size of the heating/cooling system will be substantially smaller, with corresponding less cost. The house will be much more comfortable in all seasons, without cold spots.

When the air inside a home is so dry in winter that humidification is wanted, the reason is almost always far too much air leakage. Human occupancy produces moisture, and excessive air leakage flushes out that moisture, resulting in dryness. Excessive air leakage is something that costs money, makes the house more uncomfortable, and cannot be controlled. The old adage "the house should be tight, but not too tight - the house has to breathe" is woefully wrong. The occupants have to breathe, while the house has to avoid moisture accumulation problems. The only way to achieve the best result is to make the house as tight as possible and provide mechanical ventilation, so that the right amount of fresh air is provided all the time. In this climate (heating-dominated), efficiency is gained by heating the incoming fresh air with exhaust air, through a heat exchanger. The device is a heat recovery ventilator (HRV).

The thought of active humidification in winter for a house that isn't very tight should make you stop and think some more. Where is all that moisture going? If it is leaking out through the walls and into the attic space, you may wind up with condensation on cold surfaces where you don't want it, leading to rot and mold.

While geothermal heat is an option that functions well, with high coefficient of performance, the cost usually is substantially higher than for other types. However, if a new well is to be drilled for the house anyway, then the incremental cost of geothermal for a low-demand house can be more attractive.

Today's cold-climate air-source heat pumps have come a long way toward providing a good choice for heating and cooling. They can realistically provide all the heat needed down to below zero, particularly for a very well insulated house. To be sure, the energy needed to "pump" heat up from below zero air temperature to indoor temperature is greater than when the outside air is milder, so that the coefficient of performance drops accordingly. If you feel that you want supplemental heat for extreme conditions, then electric resistance heat is your best bet for the few hours each heating season when you may need it, being low cost to install.

The building science behind all of the above is well-established and easily found on sites such as greenbuildingadvisor.com and buildingscience.com.

I think they mean they are using data from multiple scenarios gathered over time, where you are apparently using only your own singular experience as a data point.

One more positive vote for a mini spilt. No issues at all heating last winter. We do have wood and propane as a backup. Also, mini spilts space a tremendous amount of space if the home doesn’t have a basement and the cost must be less the half of what a forced hot water or air system is



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Heat Pump & Cold Temps
 

When people use the term "efficient" for heat pumps, I think they are referring to the lowest temperature at which the heat pump will produce heat. Older technology started to lose efficiency (produce less heat) close to 32 degrees, so you needed another source of heat. Newer technology that is specifically rated for temperatures down to (or below) 0 degrees will continue to provide heat down to those colder temperatures without much additional electricity usage. Most manufacturers show a graph of efficiency vs temperature.

For the solar... PV or thermal?

I think how that may be integrated may affect some of the others' responses.

Also if you need/intend to go with a whole house generator that would equate to a fuel source and may help them suggest other options for the best integration of choices.

Heaing systems for a new home
 

I was the poster who mentioned the generator, and you are correct about a generator equating to a fuel source. Propane is a very popular generator fuel, and my thinking is that if a house has a generator, and the fuel is propane, then I would have that be a stand alone system, not providing fuel to any other system in the house. Most fuel providers offer automatic fill programs, some with pre-buy options, some not, but in order to accurately calculate the automatic fill delivery cycle, there has to be a reasonably consistent usage curve based on house size, season, weather (temperature), and family dynamic. Since it is not really possible to calculate usage for a generator , and since you certainly do not want to run out of fuel for your generator, I would keep the generator on its own system, not associated with the main propane supply for household use. Maybe somebody who has a generator for standby purposes and also uses propane for household purposes can comment on this situation.

It could be attached to a separate tank... but you would still have a supplier; and possibly get some discount pricing for the extra.

The mini-splits as far as I can tell do not supply domestic hot water... so it is a matter of how many different systems to install.

A thermal solar sized to produce just enough domestic hot water in the summer would more likely need a back-up in the winter.
One sized to produce more than enough in the winter will have too much capacity in the summer.

Just so many factors for everyone to think about with additional capital costs, suppliers, and such.

They have also come out with Floor Units for MiniSplits now in case you haven't seen those. Many don't like the look of the unit up on the wall, so this is another possible option depending on your room and layout.

https://www.mitsubishicomfort.com/re...modelID=MFZ-KJ

PV.

I plan to have a portable generator that includes 240V with Neutral (mainly for the well). 6kW should be plenty. I will have conduits installed to allow possibly a larger backup system down the line. I would like 240V, Dual Fuel, Inverter and Electric start. The only one I can find that does all that is 10kW (bigger than I'd like, but will go with that if nothing new pops up). More and more Dual Fuel/Inverters are popping up. Most dual fuel portable inverters don't have the 240V. I wouldn't try to run the Heat pumps with a small unit. I'd use the backup propane stove for heat. We've been in the lakes region for 35 years, we do go up in winter and could have used a backup generator once for one night. Just need water and fridge.

I have a portable Dual Fuel Inverter in MA. We have natural gas for heat and no Well and I get by with 3.5kW fine.

Originally I was planning on a propane Forced Hot Air or Forced Hot Water system. But after learning how crazy efficient Heatpumps are now, and that they can be powered by PV Solar (Net Metering) I've changed my tune. We have Ultra Efficient Natural Gas forced hot air Heat (and cool) and Tankless Natural gas Hot water in MA and it works great. But we have natural gas, which is really cheap. Propane by the tank is expensive, but I believe I will have some sort of propane tank no matter what we choose. Mainly for backup Heat, Generator and maybe hot water. A plain Jane electric hot water tank might be our best bet if we have PV Solar. I'm not 100% sure PV is gonna work out. Have to see what things look like after some trees come down.

EDIT: Just reread your post camp guy. I'm not sure it's worth doing a separate tank for generator. Just size things for other uses with a little more safety margin.

Still can't decide on heating system. Tried to get one Geothermal place to show up and they just disappeared. Now trying two more. Gonna cost a fortune for geothermal though, not sure it's worth it.

Fire department did training exercises at the old cabin this morning, then burned it to the ground. I have insane pictures and videos, but not sure I feel comfortable posting them. My heart stops every time I look at them. It was a real eye opener seeing your home burn down. They drilled and pumped water from the lake. Make sure you do EVERYTHING possible for fire prevention.

First photo is a sketch of what we are building.
Second is a similar home using the colors we chose for siding and windows, and I morphed it onto a picture of our property to see how it will look.
Third is what it will look like inside.

https://live.staticflickr.com/65535/...de59cc_h_d.jpg

https://live.staticflickr.com/65535/...f4ce24_h_d.jpg

https://live.staticflickr.com/65535/...715691_h_d.jpg

Magnificent exterior design and excellent color choice.

Great house! Gorgeous but not flashy, and I'm guessing from the photo you'll be able to integrate it well with the land. Are you going to be able to keep the young trees right next to the house, or is that a vestige of the other property?

Those young trees are actually from the house photo I cut from. We actually had some similar trees in and around the old house, but they have to come down for construction. The property is LOADED with trees. 450 ft of frontage, mostly untouched. Can always put a few trees back, but I don't care for trees to close to the house that can later be towering monsters. They just cause too many problems and not safe.

There will be quite a disturbance in and around the house for construction. Most likely will need blasting. I was talking to our landscaper about restoring the natural landscape. He said he gets lots of requests like that around the lakes and he said it's VERY hard.

I love the yard because it's zero maintenance. Even the leaves just magically get blown out and leave the pine needles. He suggested not bothering to do any landscaping for at least a year and he'd research more how to get that natural landscape back. I love not having to cut a lawn or use any chemicals to maintain a lawn.

Not long after I commented in post #3 above, our 25-year old geothermal unit in CT went kablooie. We had it replaced with a brand new unit in November. I was assuming the types of incentives we took advantage of when we had it installed 26 years ago might no longer be available. But I was wrong. Some are anyway.

We replaced the basement unit with a new 5-ton Hydron Module Revolution 2. New filter box/MERV 13 upgrade, connection to our existing AO Smith hybrid pre-heat water tank, and a new Honeywell thermostat that allows control from our smart phones (though I haven't downloaded the app yet).

$15K to our contractor. We've since received a $4,025 rebate from Eversource and a 26% federal tax credit that we'll take advantage of this tax season (if you can't use it all, you use the rest in future years). This nearly cut our cost in half.

Of course, all I needed to do this time was replace the failed unit. No ductwork, no fresh air controls, no drilling a well (which I'm guessing you'd opt for given all your ledge), no connection to the interior unit. My point however is to not overlook the incentives that might be available.

I've said before on this forum, if geo is available, we'd never go with anything else. Such a comfortable heat source, eco-friendly, safe (no fossil fuels), quiet, very low maintenance and it's saving us lots of money in heating (and cooling but we seldom use that since we're usually at the lake in the summer).

Good luck and the house looks beautiful.

I would go with mini splits, solar , and Rinnai wall units.

Thanks for the honest follow up.

There are incentives on mini splits and other high efficiency systems.
We took full advantage of incentives in MA on our Solar and heating system.
Break even on Solar was approx 6.5 years.

Current estimate on Geothermal is $40-$45K before incentives.
Any complete system isn’t cheap. I have not got an estimate on mini split yet. But with that and hot water etc. I’m guessing it would probably be $20K plus incentives.

We plan to put Solar in regardless of which heating we go with. If it’s feasible. We have a LOT of tall trees around the house. A few are coming down for construction. We will see how it looks once those are down. I think before trees were down not quite enough sun was getting in. Now with a few down it looks promising. But a couple more are coming down, now that house is out of the way. Roof angles for panels will be tricky too.

I know about the Solar shingles, which as far as I’ve researched are just not practical yet. Prices are staggering. Probably over $100K at least for Tesla installs. And you’d probably have to wait a year or two to get installed.

What Rinnai wall unit you referring to? For hot water?

If you’ll notice we didn’t put a fire place / chimney. But we were thinking of a vented propane stove. But after seeing old house burn to a crisp we are having 2nd thoughts of any propane. It really really hit us both. Maybe eventually I’ll be brave enough to post some photos, unless it’s your own it Matt not impact you like it did us. Never expected to feel like this. When you see smoke billowing out of the bedroom you slept in it’s scary. Even though it was all planned. But you can see what can happen. In just 1 year we were sentimentally attached. That’s just how we are.

Noisy heatpumps
 

Non-resident neighbors on both sides of me added heat pumps in the past year. The quiet neighborhood is no more. The outdoor units are noisy and the compressor and fan noise carry in the still cold winter air. They rarely stop, especially when it is cold. On some nights, I can even hear one of them while in bed. Seems wrong that an unoccupied house should make so much noise.

That's a good point, what brand are they.

Very interesting--do you know what the payback period is for an all new geothermal system, including all the incentives? As msw notes, solar is about 6 years, I'm wondering how geothermal compares.

It depends what you are comparing too. See this link on costs to operate different systems.

https://www.efficiencymaine.com/at-h...st-comparison/

Install guesstimates

Oil Burner $15K
Geothermal $40K
MiniSplit $15K

So going from say an existing Oil Burner (which is "free") to Geothermal

Oil Burner $2588 per heating season.
Geothermal $1643 per Heating season.

You save $945 a heating system.

So it would take ~40 years.

Going from existing Oil Burner to a Mini Split

Mini Split $1795 per heating season
Oil Burner $2588 per heating season.

You save $793 per year.

So it would take 19 years.

But you also get cooling !!!

Let's say you had a MiniSplit and wanted to go Geothermal

Mini Split $1795 per heating season
Geothermal $1643 per Heating season.

You save $152 per year

It would take 265 years to break even ;)

In my case I don't have an existing system (or your old system is shot)

So we need to compare the difference in price divided by the savings

Difference between Geothermal and MiniSplit is still $25K and the savings is still $152 per year (for heating). Let's double that because that was just for heating and we want cooling out of both systems.

It will still take 83 years.

You can argue all you want on my estimates. But Geothermal is super expensive and the difference in savings is really small comparing to a mini split.

You pretty much have to ignore ROI for Geothermal and just decide if the aesthetics are worth it over a mini split. Because Mini Split wins bye a mile no matter how you slice it, money wise.

You are also better off putting that $25K increase in Geothermal over a Mini Split into a Solar system (which will run either system for free) :) And you only need to make the Solar System 8% larger (~$2000) to cover for the less efficient Mini Split.

I didn't include the incentives but most of the incentives apply equally to MiniSplits as well because they are nearly as efficient as Geothermal.

$2600 in oil just for heat?
What are they estimating the price of oil at?

I don't know Flying. We did that analysis 26 years ago when the incentives were great for a new build install. I don't recall for sure what the payback scenario was at the time but I believe it was in the 7 - 8 year range.

The geo units are much improved now too. Last night the temp got down to 5 below F and the house was a comfortable 66 degrees (what we had the stat set at) with no need for the electric back-up (I have those circuits turned off at the panel). Our older unit would have required the back-up at about 5 degrees above. Our electric bills last year were about $425 per month in January & February (4,000 SF very tight home) which, of course, includes lighting, hot water boost and appliances. That was with the older unit. Our January bill this month is $307 with the new unit and higher electric rates due to the gas supply woes in the northeast. We keep the temp at 66 night/69 day and there are only two of us in the home.

Why would the geo be affected by ambient air temperature?
Is it not sized large enough to meet the BTU requirements of the space?

Look at the link. $3.10 / gallon you can set prices of fuel to what every you want.

But you make a good point, they used $0.22 / kWh for electricity so that's a bit higher than most of NH so Geothermal and MiniSplit would be even that much cheaper to run. I don't know the going price of oil, but that sounds close. No idea what they are using for a size house. But it's just for rough estimates and comparison shopping.

Bottom line, oil will cost about double Geothermal or MiniSplit. And Geothermal will cost about double to install over Mini Split or Oil.

House size really not something that would factor in as the estimate would be for the same available BTU.
It may factor in on the number of units necessary to achieve a comfortable temp in various areas of the home... but that would be an on-site assessment variable to each.

I can prebuy oil, but not electricity. $2.899 is what I'm at.
But what I noticed was a friend using the same system but choosing to heat with wood only save about 100 gallons... maybe 150 this year due to the longer duration of the cold spell.

The rest of what we used was for heating water and standby when the water was to be heated but not used.

My home may be better insulated than his... but the heated space is about the same along with the number of occupants.