New house construction in southern California

[CharlieEscCA]

Any thoughts on whether a heat pump or propane furnace is a better choice for a new house at 2000' elevation in San Diego county? Because of Title 24, I'm suspecting my house will be much more efficient in terms of heating (and cooling) needs than my current house.

I'm also thinking that regardless which technology I choose, a variable speed air handling system will be a better choice for comfort and noise considerations (and perhaps lower kWh usage for the motor?).

Any thoughts?

[Mike90250]

What energy source will you have best access to ? If you have a lot of blackouts, propane furnace. If you can't get a propane truck up there in the muddy winter, heat pump

Note that below 35F, heatpumps cease "pumping" and usually turn on an auxiliary electric heater coil.

[J.P.M.]

Any thoughts on whether a heat pump or propane furnace is a better choice for a new house at 2000' elevation in San Diego county? Because of Title 24, I'm suspecting my house will be much more efficient in terms of heating (and cooling) needs than my current house.

I'm also thinking that regardless which technology I choose, a variable speed air handling system will be a better choice for comfort and noise considerations (and perhaps lower kWh usage for the motor?).

Any thoughts?

Charlie: Propane hands down.

Lots of reasons, but mostly for comfort of warmer temps. at the registers and heat if/when the power goes out. Another consideration: It's hard to get an air source heat pump sized right around here for summer and winter loads which are quite different. Winter design temp. ~ +26 F. Summer is 97F. w/ a 69 F. design dew point. Winter heating load is greater than summer making a heat pump that's correctly sized for summer loads perhaps undersized for winter, and a winter sized heat pump oversized for summer. "So what" you say. "It'll operate less and I'll stay cooler for less run time if I'm oversized for summer. I'll use less electricity too." Well, oversizing an air conditioner makes for a very moist and what many consider an uncomfortable environment, and, it'll probably cost you more in electric bills to run a larger unit as it cycles more often. Details on reasons why air source heat pumps and low energy homes aren't the best match on request. another factoid: Because the Title 24 low loss home gets an added boost from mostly uncontrolled heat additions from lights, appliances, cooking, showers, etc. offsetting more of the heating load, the heat pump does not operate until lower outside temps are reached. That means it operates at a lower C.O.P. (EER or SEER to use common parlance). That costs more in electric usage and more $$.

You'll have a title 24 home with a low HVAC load. I'd consider mini splits for A/C as needed and a high efficiency propane condensing furnace for winter heat. That's exactly what I designed for the desert home I described in a prior post, although the plan there was to use passive solar and lots of thermal mass, and probably avoid most or all aux. HVAC requirements.

I like heat coming out of a register at something like 120 - 130+ F. or so. Most heat pumps puke out at ~ 90-100 F. To some, that feels like a cold draft. But, opinions vary.

All that said, if you have a heat pump with an actual, working C.O.P. > ~ 2.0 or so in heating mode, the electricity to run it will probably cost you less than the equivalent amount of winter heat supplied by propane, provided the electricity is bought at current SDG & E winter prices, even if propane is bought at cheap summer prices. If you get propane, get a large tank, at least 500 gal. Reason: You want a large enough tank to get through the winter and only buy propane in ~ July -August. If you run low in Feb. for example, you'll pay top buck - ~ $3.50/gal. last winter for example. I just got a fill up about 3 weeks ago for $2.12/gal. It's been as low as $1.65 in summer and as high as $3.90 in winter in prior years. Moral to the story: Buy in late summer for cheap and get a tank large enough to ride out the winter.

If you don't know, most propane sellers will not fill a tank > 80-85% or so, and maybe try to B.S. you into less in the summer based on the propane get "too hot" in the summer (that's' B.S. BTW). Also, it's probably not a good idea to run the tank down below ~ 10 % or so. That means actual usable volume is ~ 0.8-0.1 = 0.7 or 70%. Maybe a 250gal. tank will work with your lower Title m24 reduced loads, but I'd still go for a 500 gal. tank leaving you .7*500= 350 gal. usable vol.

Any info you'd like to share on new house location. I can see most all of Valley Ctr. that's north of Turner Lake from where I sit.

[CharlieEscCA]

I'll be 2000' west of the Blackington private airstrip.

My current house is propane, and actually annual heating costs pale in comparison to back in Illinois. But, since I'm probably still likely to go solar at the new house (even with the recent changes reducing the revenue side of the equation, SDGE rates still make solar a good investment IMHO) as besides an economic payback I will likely need solar for Title 24 credits (I have an great west view that I plan to take advantage window wise, and Title 24 does not like west windows).

When I get to the point of having a house design, I'll have the manual J calculation and heating calculations done and then figure out if a heat pump makes any sense. I know natural gas is an easy no brainer over a heat pump, but I was unsure whether a heat pump (with solar to cover significant portions of the electric use) might make sense vs propane.

[J.P.M.]

I'll be 2000' west of the Blackington private airstrip.

My current house is propane, and actually annual heating costs pale in comparison to back in Illinois. But, since I'm probably still likely to go solar at the new house (even with the recent changes reducing the revenue side of the equation, SDGE rates still make solar a good investment IMHO) as besides an economic payback I will likely need solar for Title 24 credits (I have an great west view that I plan to take advantage window wise, and Title 24 does not like west windows).

When I get to the point of having a house design, I'll have the manual J calculation and heating calculations done and then figure out if a heat pump makes any sense. I know natural gas is an easy no brainer over a heat pump, but I was unsure whether a heat pump (with solar to cover significant portions of the electric use) might make sense vs propane.

Charlie: Thank you. Where in IL ? I'm ~ 4 miles or so mostly due south of the airstrip and have a clear view of it from ~ 1,400 ft. el. I may be able to see your new digs from my kitchen window.

I'm not sure you have natural gas service on/near that road. That would be the fuel of choice if available.

Planning another ground array ? More FWIW, I'll be estimating some array revenue numbers for N. County as soon as new rates and times are approved and effective, probably looking like 09/01 or so. That estimate will include a SWAG at optimum orientation to max. out revenue under new rates and TOU times for DR-SES.

FWIW, that west fenestration will be pretty expensive in terms of added cooling load. I'd think about exterior moveable covering. Just sayin'.

The Title 24 credits are nice, but the big savings are probably in lowered bills over time and more comfort. Opinions vary.

[bcroe]

Any thoughts on whether a heat pump or propane furnace is a better choice for a new house at 2000' elevation in San Diego county? Because of Title 24, I'm suspecting my house will be much more efficient in terms of heating (and cooling) needs than my current house.

You might note the variation in propane prices over the seasons. Ours has varied from $1 to $5.25 a gallon
(of course at the absolute coldest time) in one year. At $2.25 its a break even between propane and resistance
electric, a heat pump wins.

The price spike occurred because with a surplus in summer, the suppliers started exporting it. Then when local
demand peaked, somehow there weren't enough pipelines to supply everyone: oh what a surprise, might as
well cash in. I didn't buy any, my grid tie does it all here in northern IL. Bruce Roe

[J.P.M.]

You might note the variation in propane prices over the seasons. Ours has varied from $1 to $5.25 a gallon
(of course at the absolute coldest time) in one year. At $2.25 its a break even between propane and resistance
electric, a heat pump wins.

The price spike occurred because with a surplus in summer, the suppliers started exporting it. Then when local
demand peaked, somehow there weren't enough pipelines to supply everyone: oh what a surprise, might as
well cash in. I didn't buy any, my grid tie does it all here in northern IL. Bruce Roe

Hence, my suggestion of a 500 gal. or larger tank. It's all about supply and demand with summer demand around here being low.

[bcroe]

Hence, my suggestion of a 500 gal. or larger tank. It's all about supply and demand with summer demand around here being low.

Here most everyone has a 500 gal tank, which sets you up for a refill at the worst part of
winter and price. A 1000 would do it here; check past bills to see what covers your situation.
Bruce Roe

[J.P.M.]

Here most everyone has a 500 gal tank, which sets you up for a refill at the worst part of
winter and price. A 1000 would do it here; check past bills to see what covers your situation.
Bruce Roe

Sizes vary by region. 250 gal. seems to be standard around here in the non tundra regions.

[SunEagle]

Here most everyone has a 500 gal tank, which sets you up for a refill at the worst part of
winter and price. A 1000 would do it here; check past bills to see what covers your situation.
Bruce Roe

I think the OP is in San Diego so the need to heat should be less then what you use in IL.

[CharlieEscCA]

Yes, San Diego area. Current tank is 320 gallons. Been in current house 28 years. Propane has been between less than a dollar to about $4.50 over the years. In general, last few years have been around $1200 for the entire year (propane 97.5% efficient furnace, propane hybrid tankless water heater (1.5 gallon water tank), propane gas range).

Architect has discussed outdoor mounted shade system (keep reflected heat outside, not inside the window). From other VC friends further east than me, I should expect a few nights temp dipping to maybe 29F, but then winter daytime highs typically 60 to 80, occasionally 50's.

Haven't checked for natural gas, but I'd be shocked if its anywhere near. Have 8" water line down my 20' wide paved fire access road. But getting electric to the planned house location is my current big project. Trying to go in with neighbor due north who wants to split costs -- that would be 520' to a pole, vs 1200' to my current easement that gets me to the my east northeast neighbor's transformer.

While house will be well insulated with double or triple pane windows, E glass, I will again likely be dealing with volumes (high ceilings) to heat and cool. With all the property, likely to go ground mount again, though solar may play into the west outdoor space shading. But with a lot that has great west views and a slope down towards the west (2000' to 1810' over 1050' of property line), ground is a likely approach over putting something on the roof.

IL was Chicago suburbs, west and northwest. Also went to U of I (College of Engineering), but they are dead to me post removal of the Chief.

But, back on heating and cooling, anyone have experience with the variable speed air handling? If it keeps temps more level, it does seem as if comfort would be better vs the two to three degree swings in a single stage system.

[J.P.M.]

Yes, San Diego area. Current tank is 320 gallons. Been in current house 28 years. Propane has been between less than a dollar to about $4.50 over the years. In general, last few years have been around $1200 for the entire year (propane 97.5% efficient furnace, propane hybrid tankless water heater (1.5 gallon water tank), propane gas range).

Architect has discussed outdoor mounted shade system (keep reflected heat outside, not inside the window). From other VC friends further east than me, I should expect a few nights temp dipping to maybe 29F, but then winter daytime highs typically 60 to 80, occasionally 50's.

Haven't checked for natural gas, but I'd be shocked if its anywhere near. Have 8" water line down my 20' wide paved fire access road. But getting electric to the planned house location is my current big project. Trying to go in with neighbor due north who wants to split costs -- that would be 520' to a pole, vs 1200' to my current easement that gets me to the my east northeast neighbor's transformer.

While house will be well insulated with double or triple pane windows, E glass, I will again likely be dealing with volumes (high ceilings) to heat and cool. With all the property, likely to go ground mount again, though solar may play into the west outdoor space shading. But with a lot that has great west views and a slope down towards the west (2000' to 1810' over 1050' of property line), ground is a likely approach over putting something on the roof.

IL was Chicago suburbs, west and northwest. Also went to U of I (College of Engineering), but they are dead to me post removal of the Chief.

But, back on heating and cooling, anyone have experience with the variable speed air handling? If it keeps temps more level, it does seem as if comfort would be better vs the two to three degree swings in a single stage system.

Understood on all. Keep the shading outside and moveable and the heat will stay outside.

On fenestration, south and east glazing will tend to add winter heat and west glazing will tend to add summer heat. Although Title 24 glazing requirements make passive solar winter gains much smaller than straight double glazing will accomplish.

On temps: my 10 yr. averages are different than ASHRAE design temps., but are probably pretty close to what your property has experienced over the same period.

Daily average high temp: Average = 76.5 F., highest daily high = 106.5 F., lowest daily high = 44.3 F., std. dev. = 11.4 F.
Daily average low temp.: Average = 55.0 F., highest daily low = 82.0 F., lowest daily low = 31.3 F., std. dev. = 8.2 F.
Daily average temp.: Average= 63.1 F. highest daily 24 hr. average = 94.5 F., lowest daily 24 hr. average = 38.2 F., std. dev. = 9.6 F.

On air handling, multispeed blowers will change noise levels. That noise reduction from reduced air circ. may not be quite as big an advantage as in the past because Title 24 ducts are insulated more than prior ducting requirements. That extra insulation will reduce the noise some as well, maybe 3-6 db or so. Increased flowrate will also improve air circ. in a well balanced system, but make distribution problems, such as they may exist, worse on a not so well balanced system, with system balancing usually more art than science. Not oversizing a system is one way to keep noise and flow maldistibution down. Smaller, but still adequate systems will have a higher duty cycle and run more, but be quieter about it. load balancing and flow distribution, to the extent needed, can often be done with duct booster fans and ceiling fans, particularly for high ceilings. Keep air velocities low to help avoid unnecessary and uncomfortable drafts and air currents, particularly if heating is with a heat pump. That means bigger ducts for larger air handlers and larger flowrates.

Get a big whole house fan. The big ones make less noise which is mostly f(blade tip speed). Just be sure to find a way to close it off and insulate it for winter. Otherwise, it'll be a real heat sieve.

[Mike90250]

My 3 cents
Winter time thermal gain from title 24 windows = 0. Windows are designed to reflect heat to reduce air con costs, not allow for winter heat gain. It sucks
Has the house been built yet ? Do you have ez access to firewood ? Consider a Masonry Heater (first link)
2 posts to view
https://www.solarpaneltalk.com/forum...446#post357446
https://www.solarpaneltalk.com/forum...icated-to-work Oven ignitions systems

I use a $15, 20" box fan in the attic hatch as a whole house fan.

[J.P.M.]

My 3 cents
Winter time thermal gain from title 24 windows = 0. Windows are designed to reflect heat to reduce air con costs, not allow for winter heat gain. It sucks
Has the house been built yet ? Do you have ez access to firewood ? Consider a Masonry Heater (first link)
2 posts to view
https://www.solarpaneltalk.com/forum...446#post357446
https://www.solarpaneltalk.com/forum...icated-to-work Oven ignitions systems

I use a $15, 20" box fan in the attic hatch as a whole house fan.

Mike: 20" box fans do work, but the idea behind whole house fans is to move approx. an order of magnitude more air than a window fan can move, probably something between 8,000 and 12,000 actual CFM for a, say, 2,500 ft.^2 dwelling. A window fan will sure help, but compared to a whole house fan, it's not in the same league.

One safety/precaution/important consideration: Large suction rates can produce negative draw on chimneys, etc. Vents (windows, etc.) need to be open before the fans are turned on. This is important to prevent furnaces not venting safely.

On masonry heaters, they're about as efficient as a decent wood stove in terms of net heat delivered to a dwelling, maybe a bit less so. Most of the advantage of a masonry heater is in the thermal mass it provides and that mass's ability to even out heat demand. I'm a big fan of thermal mass, but added in a more distributed way via ICF or other ways that will accomplish the same thing as a masonry heater or other more concentrated mass arrangements in a better and more flexible way. The thermal mass heats/cools slowly and in effect acts as, and adds thermal capacitance to the dwelling, by what can be a variety of mechanisms and arrangements. Masonry heating systems sort of combine the advantage of a massive fireplace while improving on the efficiency of a fireplace, which we all know to be very low or even negative.

There's a lot of ways to use thermal mass. ICF type construction is one, but there are others. I've not mentioned them as I suspect Charlie isn't into such construction.

Interestingly, a home with a lot of thermal mass, or thermal capacitance needs a slightly different approach to nocturnal cooling. that nite ventilation, forced or natural, will still work, but flow rates and cooling (or heating) times need to be treated differently.

On an unrelated matter, for your stove ignition problems posting, when I saw that post, I was wondering why you just didn't use a match when high tech fails. Seems a fine, low tech solution. It's also what everybody used when I was a kid and well into adulthood.

[Mike90250]

......On an unrelated matter, for your stove ignition problems posting, when I saw that post, I was wondering why you just didn't use a match when high tech fails. Seems a fine, low tech solution. It's also what everybody used when I was a kid and well into adulthood.

The stove computer controls the gas valve. The thermister controls the burn time of the fuel. Without the module working, the gas does not turn on. No gas present for the match to light.
Like lawnmowers that turn themselves off when you let go the blade clutch.... Or the new sealed emission gas cans that dribble fuel all over everywhere, but into the lawnmower
"we know better than you"

On masonry heaters, they're about as efficient as a decent wood stove in terms of net heat delivered to a dwelling, maybe a bit less so.

Actually, no, they deliver more BTU's than iron stove (iron stoves send at least 60% of the heat out the flue), and emit less pollution then a 1 yr old catalytic stove.
They take at least 24hr to begin to radiate heat from a cold start (but after the last fire, they will provide heat for another 24 hours)

http://mha-net.org/docs/position.PDF

EPA exemption