Opinions on Hot water sources wanted

[tkappeler]

Yes, I should have mentioned the necessity for a thick skin here :laughing:

I hear ya, that is the challenge of green energy. I don't know what all the code requires you to do to meet energy efficiency standards, but the R-26 walls and R-42 ceilings are not onerous or unrealistic. I would say those are minimal standards actually. What is onerous is the permitting and compliance process. It's easy to conflate the two.

I will not add any more stress to your life, building a home may be the second-leading cause of divorce :laughing:

Dave,

You are not adding any additional stress. There has to be middle ground on implementing green technologies. Some, and I emphasize some, in the green community consider anything less than LEED platinum is insufficient. There is always a cost/benefit analysis and builders (whether commercial or homeowner) need to do the best they can. If the buyers do not value the benefit, it won't happen.

 

[radioman]

First - I'd stay away from traditional tanks. They are cheap to replace -- but you need a chimney for it. A high efficiency one with the power vents is the new norm now and quite frankly - its best suited for replacements and new installs. I too have thought about tankless models, but shied away from it due to the fact that the opinions on using it varies so much- its ridiculous.

propane or electric? I really dont know - things can change 10 years from now, and most tanks last from 10-20 anyways - but the operating between types of fuel cost factor will not change much within the 10 years. They all go up . When you reach the replacement time - that is when you know which fuel type to switch to. Most of the time the cost of switching fuels is enough not to switch (ie wiring vs fuel lines).

 

[sodamo]

My apologies Mudstopper, my reading of the OP, didn't include DYI.

That said, you might be surprised that we likely disagree much less than you might think. Now that my house is past the permit/inspection phase I would definitely consider DYI solar HW and a system such as your might be a good starting point.

David Sent from my iPad using TractorByNet

 

[muddstopper]

My apologies Mudstopper, my reading of the OP, didn't include DYI.

That said, you might be surprised that we likely disagree much less than you might think. Now that my house is past the permit/inspection phase I would definitely consider DYI solar HW and a system such as your might be a good starting point.

David Sent from my iPad using TractorByNet

No apoligies really needed. As long as we still have the right to express our opinions in this country, people will continue to express their opinions. I have a habit of sometimes over expressing mine. Something to do with granite for a brain I think.

Everything else aside, the Op seems to also have cosmetic concerns. I can see where some folks might not want a solar collector on their roof or hanging on the side of their house. He also questions appreciation values of a home out fitted with energy efficient divices. There also seems to be the question of payback on the initial investment. These are things only he can decide for hisself. I will say from my personal perspective, I would be more app to purchase a home that cost less to live in that a similar home with higher living expenses. As to payback, this can get very muddy. When I look at the cost of energy systems on a part by part basis with a diy in mind, and then look at the cost of a complete system with install I start getting upset. You cant always get any rebates or tax incentives if you do it yourself, and all the rebates and tax incentives seem to be eaten up by the company that is installing a qualifying system. It seems to me the installer knows what kind of tax break or rebate you are getting and he jacks his price up to reflect this, keeping you from saving any money at all. I can purchase individual solar cells and build my own panels for about a 10th of purchaseing a factory assemble panel of the same size. I can take about $100 worth of materials and build a solar collector that if factory made would cost 5 times as much. The difference is I am doing all the work, but I wont get any rebates or credits for it. All I get is to save the money it would have otherwise cost me to purchase a similar factory built unit. DIY is not for everybody, not everybody is willing, or able, to sit for hours soildering solar cells together to make a complete solar panel, and not everybody wants to build solar collectors and install them theirselfs. Also the building inspectors seem to have the attitude they know it all and the homeowner knows nothing. In my area, the inspectors are the folks that couldnt make it building houses so they became inspectors instead.

 

[sdkubota]

Seeing the recent thread on tankless water heaters is causing me to revisit my hot water sources for the new house to be underway soon. I have in my plans an electric hot water heater but am having buyer's remorse or something like that. The background:

No natural gas but I can use propane.
No chimney in the plan nor any place to take one out ... not at this late hour anyway so electric or high efficiency (PVC) piping is a must
Water source will be well.

Drawing energy usage comparisons between propane and electric heaters has been confusing ... it's like comparing apples to airplanes, especially when you factor in the intangibles like heat recovery times, regional price differences on electric/propane, initial costs vs operating costs, etc.

My options are:

Traditional electric hot water heater (40-50 gallon)
High efficiency gas water heater (40-50 gallon)
Tankless gas water heater (8.0 gpm or better) (with or without a small electric to avoid cold slugs through the line)
Hybrid electric heat pump water heater.

Any insight you can provide is always greatly appreciated.

I have an 85 gallon Marathon electric water heater and couldn't be happier. In fact my entire house is electric which qualifies me for reduced electric rates.

 

[muddstopper]

mudstopper - The 400 watts is the instantaneous power produced, if it does that for an hour, you will have produced 400 watt-hours. So, per alternator, it would be 400 watts X 24 hours = 9,600 watt hours per day X 30 days per month = 288,000 watt-hours, or 288 kilowatt-hours per month per alternator.

1200 kWh per month / 288 kWh per alternator = 4.16 alternators needed (not allowing for any losses)

You are fortunate to have the hydro resource, go for it. Even if it produces only half your needs, that's a considerable amount.

I knew there was something wrong with my math, the numbers where just to high. What you have suggested makes more sense. In my current house we use the 1200kwh average monthly. This house is 30 years old and not really energy efficient. My intent is to incorporate a lot more energy efficient building materials in our retirement house. I also have some wierd ideals for heating and AC. These ideals we are currently experimenting with at a friends house with promising results, but not where I want it to be just yet. Most of our problems are with the sizing of the heat exchanger for AC system, which is geothermal in nature. We can get cold air, just not enought to be a standalone system. It might be interesting to note that this system design had no visible features for those that are concerned about cosmetics.

 

[sparc]

In warm climates one of the cheapest and simplest solar water heaters is a batch system. Mount a steel tank where it gets sunshine and you will have heated water. There is no reason a batch tank couldn't serve as a pre-heater. I would think Hawaii would be a reasonable location for a batch heater or pre-heater for an on-demand unit.

At my brothers place in Ocean City, NJ i helped him put up something similar to what you describe.
a 30 gal tank laid horizontal on the roof where it got sun all day. it was piped to an outside
shower that he used when he came back from surfing. he said it made plenty of hot water
year round as long as the sun was out. he would surf even in Dec and Jan when it is coldest
there. he had heat trace on the piping to keep it from freezing on the feed side. the output of
the tank was pitched so it would drain when shut off so didn't have to worry about freezing.

 

[dave1949]

At my brothers place in Ocean City, NJ i helped him put up something similar to what you describe.
a 30 gal tank laid horizontal on the roof where it got sun all day. it was piped to an outside
shower that he used when he came back from surfing. he said it made plenty of hot water
year round as long as the sun was out. he would surf even in Dec and Jan when it is coldest
there. he had heat trace on the piping to keep it from freezing on the feed side. the output of
the tank was pitched so it would drain when shut off so didn't have to worry about freezing.

I had a batch heater on the roof of the house (gravity feed) where we lived in Iran while in the Peace Corps. Is was in the city of Dezful, the southwest corner of the country, semi-arid desert type of climate. High temps of 115* in summer were common. Anyways, the tank was large enough for our daily hot water needs, most of the time we had to mix in cold water at the spigot. We made sure it was refilled in the evening, that was a manual valve you opened until water spit out the overflow. Of course the operation could be modernized to be automatic.

There were a lot of free btu's in that tank, and there are many ways to reduce energy usage that vary by climate.

 

[uglyboywith11fingers]

Also need to consider the cost of the heater itself... high efficiency gas (nat. or propane) vs electric.
Our water heaters last about 12 years, even with a water softener on hard well water.
I switched back to electric last time... $330 for a 60 US gal. electric vs. $1100 for a 50 US gal. hi-eff propane. I doubt I'd save that much money in 12 years using propane vs electric.
Pete

 

[dave1949]

I knew there was something wrong with my math, the numbers where just to high. What you have suggested makes more sense. In my current house we use the 1200kwh average monthly. This house is 30 years old and not really energy efficient. My intent is to incorporate a lot more energy efficient building materials in our retirement house. I also have some wierd ideals for heating and AC. These ideals we are currently experimenting with at a friends house with promising results, but not where I want it to be just yet. Most of our problems are with the sizing of the heat exchanger for AC system, which is geothermal in nature. We can get cold air, just not enought to be a standalone system. It might be interesting to note that this system design had no visible features for those that are concerned about cosmetics.

For cooling, I've thought about buried PVC pipes and a blower that draws in outside air, the air gets cooled by the ground temperature before entering the house. It seems like people who have tried similar methods cannot overcome the mold problems that occur when the outside air is cooled below the dew point somewhere in the pipe length. That would produce water laying in the pipes and the incoming air of course, carries mold and fungus spores.

People with under-the-house rock beds used to store heat have run into similar issues. It seems heat transfer with air is prone to this problem, even in normal AC ducting, so water-based systems may be a better choice.

My passive solar earth-bermed house is great for heating but if this summer hottest month on record stuff continues as normal, it will push me into finding a cooling solution of some sort. Evaporative cooling may not work very well here since our heat is usually accompanied by high humidity.