diy solar

diy solar

Complete rebuild of a house - how would you power and heat/cool ?

Passive solar was all the rage in the 70's. I found it fascinating, but haven't heard much about it as of late, and particularly in conjunction with or since the inception of, solar panels and active solar energy collection, specifically for electricity.

One problem is that it doesn't dovetail well with cheap cookie-cutter home building in master-planned communities. Another is that it involves orienting the home for passive solar gain, and then some thermal mass to store collected heat. Again, if all the homes face the winding streets it's impossible to incorporate these methods.

Seems like I had a book on passive solar homes way back then. If I still have it then it must be fifty years old. :oops:
 
I am curious about the basement. Is it a full 1500 square feet, like the main floor?
What is the ceiling height of the basement, main floor and attic? I'm fishing for cubic feet of living space.
What will be the square footage of the living space in the attic when it is finished?
Yes, the basement is under the entire house. Height is probably 6 feet (1.8m) since I just clear the boards (I am 5'10"). NOT finished. part of it is just like a root cellar with all brick sides and floor. Newer part reinforces the brick foundation with concrete block, cement floor.

I don't know the living space in the attic yet. Would cover the entire main floor but lose space due to the roof. So LIVING space is different than total volume.

BTW the ceilings are 12' tall on the main floor.

Wood is pure backup. Solar heat (vacuum tubes heating fluid) and/or geothermal will be the primary. Pellet stoves are nice, but that is constant $$$ outbound with no return. No thank you.
 
How much do you care about temperature control? Are + - 10 or more degree swings and some cold rooms ok? If so, and you don't mind the work, concentrate on wood heating and save some money. If you want a constant temp with no swings, then go with something modern like a ground source heat pump. That might be overkill if you were to super-insulate the place. Then maybe you could do it with minisplits, and radiant would also be overkill. How open is the floor plan? That could determine how effective minisplits could be and how comfortable wood heating will be. Also, for financing you will need some sort of central heating system, so heating exclusively with wood and no backup is out.

One way to get constant temperature in the house with wood is to use a masonry fireplace. You burn a load wood efficiently and hot once or twice a day, and it will gradually release this heat over 24-48 hours, keeping the temperature steady. I use that in combination with underfloor radiant heating (also wood fired, coupled to a 3000L water tank - count as central heating?) to keep the place nice and warm (and at equal temperature day and night) in a 110m²/1200 square feet off-grid home.
 
Passive solar was all the rage in the 70's. I found it fascinating, but haven't heard much about it as of late, and particularly in conjunction with or since the inception of, solar panels and active solar energy collection, specifically for electricity.
Seems like I had a book on passive solar homes way back then. If I still have it then it must be fifty years old. :oops:
I am NOT trying to crap up the OP's thread and I hope folks don't rant about this here but I believe numerous industries do their best to bury the "passive home" movement because those industries make more money selling and maintaining "typical" heating & cooling systems. Just sign on the dotted line, and pay this guy to maintain the system, and pay that guy for energy to run the system, forever.
Granted solar power can power the system but you have to build a larger solar system to do that.
BTW the ceilings are 12' tall on the main floor.

Wood is pure backup. Solar heat (vacuum tubes heating fluid) and/or geothermal will be the primary. Pellet stoves are nice, but that is constant $$$ outbound with no return. No thank you.
WoW 12 foot ceilings. That's a lot of cubic feet to work with.
Solar/geothermal heat sounds like a good way to go.
One way to get constant temperature in the house with wood is to use a masonry fireplace. You burn a load wood efficiently and hot once or twice a day, and it will gradually release this heat over 24-48 hours, keeping the temperature steady. I use that in combination with underfloor radiant heating (also wood fired, coupled to a 3000L water tank - count as central heating?) to keep the place nice and warm (and at equal temperature day and night) in a 110m²/1200 square feet off-grid home.
I like it.
A big ass fireplace in the basement with a few tons of stone running up through the main floor. That's a lot of stored heat.
 
WoW 12 foot ceilings. That's a lot of cubic feet to work with.
Solar/geothermal heat sounds like a good way to go.
I like it.
A big ass fireplace in the basement with a few tons of stone running up through the main floor. That's a lot of stored heat.

The good thing about radiant is that it heats the objects in the room, not the air. I also have high ceilings:

DSC09542.JPG

Besides that masonry fireplace, the concrete floor (insulated from the foundation) acts as a thermal battery as well. So you have the 3000L water tank (separate building, no cellar here) that pumps heat into the floor, effectively increasing heat storage. Once the place is warm, it takes very little to keep it warm and constant. Of course, it takes a while to get warmed up (it's a lot of mass), but you're not a slave to the stove/fire.
 
Passive solar was all the rage in the 70's. I found it fascinating, but haven't heard much about it as of late, and particularly in conjunction with or since the inception of, solar panels and active solar energy collection, specifically for electricity.
Except it works. I know many people with various types of systems and they work. Unfortunately they live too far away to visit
 
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I need to plan NOW to do it later. Even with the grid, how would you heat and cool? Why spend $$$ you don't need to? Failure to plan ... see it daily.
I have an endless supply of hardwood so I heat mostly with wood. I also have LP water heater that I heat first floor slab with. I will use electric to heat slab on second floor. I have about 18kWh of excess PV array that I can divert to heating second floor slab. On cloudy days with not enough PV output I can charge battery packs and heat floor. Total load would be about 12kW on a 14kW Kohler whole house generator.
 

One fire a day paired with thermal storage tank like upnorth suggests you have an independent system, but it’s costly 10-15k if you do your own plumbing, there maybe state rebates for “carbon neutral” heating systems.

We have a Stantec 40kwhr boiler and a 800 gallon thermal tank house was toasty warm when it was -5f at night and the high was only 6f yesterday, I just had to add a couple more sticks to the fire.

What’s cool with thermal storage tank you can pair it with solar thermal to cover free domestic hot water during the summer, and heat on the shoulder season.

Another option is modern traditional wood stove properly burning wood is key for drawing all the energy out of each stick, many stoves can go 10-12 hours. Down side is it’s a point heat source, which is traditional for houses of that era but not up to today’s comfort of 72f in each room.


As for solar PV I’d say install as much as you can, hook up strings to combiner box, say 10 strings 2kw each, only close in the strings you need for your load at the time. As your demand increases, start closing in strings to bring on more KW.
 
I need to plan NOW to do it later. Even with the grid, how would you heat and cool? Why spend $$$ you don't need to? Failure to plan ... see it daily.

I think based on simplicity, I highly recommend the high-SEER rated mini-split HVAC solutions (for their ease of installation and incredible efficiency). I have installed two of them (mine happened to be Mr Cool brand, since I wanted the pre-charged line-sets for even easier installation). I installed a single-head unit for my insulated shop, and a 4-head unit for my brother-in-law's home, and can testify to their efficiency. If it gets really cold over there, you want to look into the newest style, latest-gen units which are designed to operate well and efficient even down to and even beyond -10 degrees F...


My Mother also has a 4-head Daikin mini-split in her house for 15 years now, and she says it has saved her a ton of money over the years. They're also very quiet, you barely notice any sound from them, just a quiet whish kind of air noise if they spin-up a little more sometimes.

But mini-splits use inverter technology and have all DC variable speed motors for their fans and compressor so they can spin them down very slow and only ramp up and down the speed gradually, depending on realtime demand. They are also most friendly running on battery power, inverters and such, since they only soft-start, and don't draw much a lot of the time.

Engineer775 on You Tube has some good videos on mini-splits for off-grid or solar environments. He's even installed some of the native-DC 48v ones that can run right off raw battery bank power...

The first type (like mentioned above) are the traditional ones where they use air-to-freon condenser units mounted outdoors and are subjected to normal outdoor ambient temperatures.

Then they have other style mini-split setups where the condenser unit can exchange heat from antifreeze liquid pipes running underground (a type of geo-thermal piping system), so that the condenser is more subjected to the average year-round temperatures found underground (instead of contending with ambient outdoor temps to interact with). That type is best for arctic temperatures, below -10 degrees F, or just make for even higher efficiency in mild environments.

The latter type, is more costly and requires more yard, as it requires lengthy, or deep piping, and the associated excavating costs.

Mini-split technology can also tie into hybrid hot water heaters and be used to heat water, and whatnot. Worth looking into as well.
 
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IMO heating via radiant floor or base board hydronic provide the best “comfort” for less than ideally insulated houses, why? You are pacing heat at the source of the cold air.

Mini splits are great for cooling, but they just can’t get the heat down low or close to cold walls to compete with draftyness.

For modern construction of an airtight envelope it’s not that big of a deal, but retrofitting a 100+ year old house, you could easily spend 20-30k weather tightening the farm house to then comfortably and efficiently use mini splits.

Just my two cents.
 
My Mother also has a 4-head Daikin mini-split in her house for 15 years now, and she says it has saved her a ton of money over the years.

Any issues with the mini-split? That is a good long time to run one.

But mini-splits use inverter technology and have all DC variable speed motors for their fans and compressor so they can spin them down very slow and only ramp up and down the speed gradually, depending on realtime demand. They are also most friendly running on battery power, inverters and such, since they only soft-start, and don't draw much a lot of the time.

I am seriously considering running both DC and AC to different areas. I need time (!) to research which is most economical vs efficient - run off DC or AC.
they have other style mini-split setups where the condenser unit can exchange heat from antifreeze liquid pipes running underground (a type of geo-thermal piping system), so that the condenser is more subjected to the average year-round temperatures found underground (instead of contending with ambient outdoor temps to interact with). That type is best for arctic temperatures, below -10 degrees F, or just make for even higher efficiency in mild environments.

We have the yard. Any idea which ones will do this? I will already be doing the digging so I can build DIY geothermal to help keep the animals cool in the extreme summer (rabbits don't do well in the heat) . not tough to dig a little more. :)

Thanks!
 
I am seriously considering running both DC and AC to different areas. I need time (!) to research which is most economical vs efficient - run off DC or AC.

The head units of the mini splits require 120/240AC their control circuity creates PWM/DC/VFD to alter the output to compressors as needed.

I’m not aware of any just DC powered mini splits.
 
IMO heating via radiant floor or base board hydronic provide the best “comfort” for less than ideally insulated houses, why? You are pacing heat at the source of the cold air.

Mini splits are great for cooling, but they just can’t get the heat down low or close to cold walls to compete with draftyness.

For modern construction of an airtight envelope it’s not that big of a deal, but retrofitting a 100+ year old house, you could easily spend 20-30k weather tightening the farm house to then comfortably and efficiently use mini splits.

Just my two cents.
Because they can run 24/7 with little energy use, they circulate the building air very well.
The inverter type systems are also available in the traditional USA style split system.
You will have to draft proof an older house no matter what type of heating you have. It's not expensive to do, just time consuming...well like a day when it is cold and windy. Just go around your house with one of those infra-red thermometers that cats love !!!!
 
Even stoking as infrequently as every 8 hours gets old as one gets old
fireplace in the basement
Tulikivi is meant to be in the living space so you’re not heating the basement walls and dirt.

Paying dollars gets old.
Even stoking as infrequently as every 8 hours gets old as one gets old
People did things with work for thousands of years. Filling a woodstove is light work compared to hefting cash imho

Did I miss what state/region this is?
Minisplit for heat in northern New England would be mostly unsuccessful without grid for example.
 
I would never recommend mini-splits for heating. Cooling for sure, and they'll work for heating, but that's not their strong suit. If they're supplanting a more traditional heating method, be it gas, wood, or electric, they're fine. But their strength is really for cooling where you enjoy the drafty nature, and because you don't have the cost of duct work.

12V DC is never going to be as efficient as 120, or even 240.

Just my 2cents.

I Iived in the PNW for 35 years and it's not horribly cold, but a airtight wood stove was really the ticket for comfort. Good firewood is easy to source - there's a ton of alder trees that get cut down every year and once seasoned burn hot and clean. Air conditional isn't needed - it rarely gets over 75 there. Central air furnace either natural gas or electric are the norm. Older cheaper homes got electric baseboard heaters which were horribly inefficient. The deluxe setup is still a heatpump type central system.

We're looking at moving back up there, but to eastern Washington, where it's more of a desert climate - cold winters and hot summers. If I were spec'ing hvac today I would be looking at the same quandaries for systems. The passive solar collection has merit if you're building a new place and you have the space. For a smaller home I would probably still do a central air system with a heat pump. If I was retrofitting it would be mini-splits with a pellet stove or wood stove. And definitely get the house as well insulated and sealed up as possible. Most of the homes up there have a perimeter foundation with floor joists on posts so you can insulate the floor. Here in so-Cal virtually everything is slab on grade - it really never gets much under 45 here, with a median temp of about 70. It was 82 yesterday :love:
 
Because they can run 24/7 with little energy use, they circulate the building air very well.
The inverter type systems are also available in the traditional USA style split system.
You will have to draft proof an older house no matter what type of heating you have. It's not expensive to do, just time consuming...well like a day when it is cold and windy. Just go around your house with one of those infra-red thermometers that cats love !!!!

Get a quote to spray foam an entire 100 year old construction house, let me know when it’s under 10-15k. That’s also after you gut the walls to studs. Even then your talking about 2x4 construction not 2x6 or even Uber double 2x6 construction of our brothers to the north.

I’d love a DIY spray foam system but it’s not quite obtainable.
 
Any issues with the mini-split? That is a good long time to run one.
On my Mother's system, I did have to go over there a few years ago, and take apart the 4 indoor head units and clean (vacuum and blow out with compressed air) all the dust from the barrel fans / coils, and clean the filters out.

They were bad (lots of dust), but it hadn't been done in 10+ years by that point. They weren't too horrible to take apart and clean, just have to be careful not to bend the coil fins or anything. They need to be cleaned once in awhile. It took me one evening to do 2 of them and the next evening I did the other 2...

Other than that, I think they had a fan motor fail on one of the indoor units once (they had a HVAC guy come replace that), but other than that it has worked great.

I am seriously considering running both DC and AC to different areas. I need time (!) to research which is most economical vs efficient - run off DC or AC.
For DC on the mini-split, Hotspot Energy is the main player in town... https://www.hotspotenergy.com/solar-DC-air-conditioners/

Engineer775 goes over these as well (has has a couple other videos on them too):

We have the yard. Any idea which ones will do this? I will already be doing the digging so I can build DIY geothermal to help keep the animals cool in the extreme summer (rabbits don't do well in the heat) . not tough to dig a little more. :)

I liked this guy's videos on the geothermal implementation (not mini-split style though, but a lot of good info there):


Watch a few of his videos on his channel, and search for some others. But it seems like that guy is pretty meticulous and has figured out how to get great results with his geothermal implementation. His style doesn't use mini-split though, his based on central air, but has good info as far as some of the underground and geothermal-related stuff.



More videos:


This is just the kind of thing where you have to watch lots of videos and get familiar with the different options available.
 
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