Do you save money heating with wood?

mcdougy

Minister of Fire
Apr 15, 2014
599
ontario
What is a reasonable projected cost to set up a solar whole house system? Selling it back to the utility does not need to be factored in unless its not reasonable to do so? Let's use a new ranch 2300 sqft house with a well, forced air furnace, a/c , 60 gallon hot water, and 4 occupants? The system goal would be enough solar to not need the utility co.pany at all. Detroit Michigan location.
 

peakbagger

Minister of Fire
Jul 11, 2008
5,834
Northern NH
It really depends on a lot of factors. If its an existing building, get your utility bills out for the last several years and figure out your yearly usage in Kilowatt Hours (KWh). With a new house you do not have the bills so you need to fill in some details on the ranch. Is it an energy efficient home?. If you build a Passivhaus or Pretty Good House which are both the high end in energy efficient you pay more up front but the yearly energy costs are much lower with minimal heating and cooling that normally is covered with surplus net metered solar (yes even in Detroit). Also inportant is how good is your solar exposure. Ideally you need a lot that is facing south with minimal shading from 8 AM to 4 PM. Having a roof pitch roughly equal to your latitude 42 degrees in Detroit. That is capecod roof pitch, with a ranch you need more roof space and more panels to deal with less than optimal pitch. If you go with ground mount you can set the panels to optimum angle but on flat land shading can be a bit more of issue. We would also need to know if you want hot water heating, air conditioning and heating covered by the system. A new home would have a heat pump hot water heater and cold climate minisplits with some sort of backup for very cold conditions where a minisplit is marginally efficient or outright unable heat the place.

A big assumption is does the local utility have net metering? and what type of net metering is available?. Is it the gold standard version where you can carry your surplus forever or is it a low budget version with a yearly reset date where the utility resets the meter to zero and hopefully pays you a pittance for your hard earned surplus. The reset date also factors in. A reset date in the middle of the winter means you cant carry as much surplus generation from the summer as you could with no reset date.

So your type of house, usage and net metering details all can substantially shift the size of the array. A rough range is probably 4 KW on the low end and 10 KW on the high end. Note the difference between KWh and KW. Panels only produce power when the sun is out and rarely do the panels put out the nameplate rating so you now need to go to a computer program to simulate your installation. Search for PVWATTS on the web and plug in your location and array data and it will spit out your monthly and yearly generation. So one opportunity is spend more money up front on an energy efficient home and appliances which reduces the power usage of the home for the long term or spend more on PV panels to cover the extra energy use for less energy efficient home.

So here is the number you probably want , roll the drums, $2 to $3 per watt installed, not including Federal, state and local incentives. If it was tract type development where all the homes got systems, it could be under $2 a watt. So on the low end $8,000 for 4KW system to $30,000 for a 10 KWh custom system. The federal tax credit ratchets down to 22% next year before it goes away, so a 2021 install gets 22% back from the fed. A good place to look up state and local incentives is here https://www.dsireusa.org/

Personally my smaller home farther north (close to 8000 heating degree days versus 4100 in Detroit) in a colder zone covers all my electric power use, minimal cooling and supplements my heating down to nighttime temps of around 25 degrees. I have 4.6KW of panels installed. I havent paid for power except for a service charge to be connected to the grid for over 5 years and burn 3 to 4 cords a year of wood for the balance of my heating. I sell my solar credits and that just about covers my monthly service feeI have electric appliances so no gas or propane. I do have a solar hot water system but these days its better to buy a heat pump hot water heater and put up a few extra panels on the roof. I actually have 3 arrays of different types and sizes. The price of solar has dropped since I installed my arrays but I designed and installed them myself so I offset some of the higher costs of doing them earlier. As far as I am concerned the money spent is money in the bank. I run econo boxes most of the time and run them longer than a typical car owner so my solar panels probably cost far less than what most folks spend on truck payments.

A good resource is Solar Power your Home for Dummies, there are older versions on line for free if you look around on the web or just buy the newer second edition.

A big consideration with system size is what type of vehicle you plan to drive in 5 to 10 years. Most predictions are it will probably be electric . That means you may want a larger system to cover recharging the vehicle. Most predictions to deal with climate change will be a shift to electric away from fossil fuels to onsite solar power or renewable grid power.
 
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peakbagger

Minister of Fire
Jul 11, 2008
5,834
Northern NH
Glad you liked it, I have talked several folks through solar installs plus did 4 of them myself. The only folks I run into that wish they never went solar are the ones that bought systems from high pressure solar firms and got conned into creative financing. Inevitably they said they didnt understand what they were getting into and trusted the company and the salesmen. The fundamentals arent that hard and most are commonsense and once someone understands them, it unlikely they would sign up for those high pressure deals.

I used to drive along a street in Mass on the way to project and it was always interesting to see a stretch of the street where Vivent solar did a bunch of installs. The road was north to south yet the panels on different homes faced east and west and many have large hardwoods blocking the panels. I expect the salesguys got great commissions but they are the only one smiling.
 

EatenByLimestone

Minister of Fire
My neighbors have a Vivent system. Most of their system faces West, but is shielded by a couple spruce trees. I think they are happy.
 

Riff

Burning Hunk
Nov 3, 2015
118
Virginia
So not a complete showing of savings as we don't know the previous residents heating habits but...went to check the oil level in our tank. We had approx 275 gallons left (the water is also heated with the oil) and the oil company estimated based on the previous residents habits that we should have had 75 gallons left. So, 200 gallons difference or about $445 difference over the trends from the last 5 years. Those trends are also skewed by last year not having had water running and the heat being only high enough to keep the house from freezing while it was for sale.
 

Woodsplitter67

Minister of Fire
Jan 19, 2017
1,616
Woolwich nj
So not a complete showing of savings as we don't know the previous residents heating habits but...went to check the oil level in our tank. We had approx 275 gallons left (the water is also heated with the oil) and the oil company estimated based on the previous residents habits that we should have had 75 gallons left. So, 200 gallons difference or about $445 difference over the trends from the last 5 years. Those trends are also skewed by last year not having had water running and the heat being only high enough to keep the house from freezing while it was for sale.
I wouldn't guage a savings on anyone else. The savings would be if you didn't use you wood stove and what your oil consumption would be. Say you like your house at 72. your savings would be the oil saved to keep your house at that temperature. Its really impossible to go by how someone else lived.. maybe they liked the house at 68.. or cooler than how you keep your home now..
My savings is more than what I originally thought.. Before my wood stove I kept my house at 68 during the day and 65 at night.. now my home is in the low 70s during the day and upper 60s at night.. this would cost me even more in oil and creating even more savings
 

Jason H

New Member
Oct 9, 2020
22
Hudson, Quebec
So the verdict just came in for me. Just received the power bill from Nov 9th to Jan 9th. (Our heating system is electric) and by using mainly free wood, except a quick blast from the furnace in the morning, our bill is 500 bucks less. And for those that want to get specific, the average temp was only 3 degrees warmer this year. Looking st at least 1000 dollars in savings this year I think
 

Woodsplitter67

Minister of Fire
Jan 19, 2017
1,616
Woolwich nj
So the verdict just came in for me. Just received the power bill from Nov 9th to Jan 9th. (Our heating system is electric) and by using mainly free wood, except a quick blast from the furnace in the morning, our bill is 500 bucks less. And for those that want to get specific, the average temp was only 3 degrees warmer this year. Looking st at least 1000 dollars in savings this year I think
Saving is Saving no matter how you look at it and Saving 1k is a great start. how long of a burn time do you get from your stove. Is this your first year burning
 

Jason H

New Member
Oct 9, 2020
22
Hudson, Quebec
Saving is Saving no matter how you look at it and Saving 1k is a great start. how long of a burn time do you get from your stove. Is this your first year burning
Usable heat, I'd say 5-6 hours. Coals for a relight maybe 10 hours. My fireplace is in a corner room of the house so I need more heat output than if it was in the center of my house. Yep this is my first year burning. I've always loved cutting and splitting wood and now that I see a savings I'll love it even more. I dont see myself being able to save too much more money. I brought my power bill down to 180 bucks for two months, which is similar to summer bills so there's not much room to save more
 

peakbagger

Minister of Fire
Jul 11, 2008
5,834
Northern NH
I must admit, with the relatively warm weather up in northern NH I have taken a break from running my boiler for the last few days and running my mini split for heat. I have a bunch of power credits from my solar production so its free heat. Its definitely not as good heat, my boiler is in the basement and obviously radiates heat into the floors so I have warmer floors when I am heating with wood. The minisplit is just heating air and moving it around so it tends to stratify. Still its nice break until January temps go back to normal.
 

Woodsplitter67

Minister of Fire
Jan 19, 2017
1,616
Woolwich nj
Usable heat, I'd say 5-6 hours. Coals for a relight maybe 10 hours. My fireplace is in a corner room of the house so I need more heat output than if it was in the center of my house. Yep this is my first year burning. I've always loved cutting and splitting wood and now that I see a savings I'll love it even more. I dont see myself being able to save too much more money. I brought my power bill down to 180 bucks for two months, which is similar to summer bills so there's not much room to save more
If you can go solar... I got no bill and a system that pays for itself