You can just use a plasma TV displaying a fire video :-). Mine puts out about 2000 btu - and I really do have a video of a fire.

Posted By ICFHybrid on 16 Dec 2011 08:58 AM

having a gas line break during a quake does happen and they can explode.

There are fittings you can add to your system (and probably even the meter) that will shut the gas off at the entrance in the event of an earthquake.

Good to know.

I looked into propane costs in my area and they are about equal to electric costs. I think I will go the route of doing the home all in electric, utilize an active & passive solar design, and then have a diesel generator in case of power failure.

When you make electricity by burning fuels, the efficiency of the generation process including line losses is estimated to be 30% by DOE or whoever figures out the source energy equivalents, since the source energy multiplier is 3.34. When you burn natural gas or propane in a fireplace, the efficiency values are specified, but probably range from 70% to 90+%, and the source energy multiplier is low, natural gas being 1.047 and propane being 1.01. Therefore from a carbon footprint or fuel conservation point of view, burning the gaseous fuel in the fireplace is more than twice as efficient as usiing electricity to generate the heat. (80%/1.047)/30% = 2.5. As already pointed out, electric fireplaces are probably simpler, but they are poor from a fuel efficiency standpoint.

I would take a good look at geothermal before I went with electric or propane.

Posted By Lee Dodge on 17 Dec 2011 07:12 PM
When you make electricity by burning fuels, the efficiency of the generation process including line losses is estimated to be 30% by DOE or whoever figures out the source energy equivalents, since the source energy multiplier is 3.34. When you burn natural gas or propane in a fireplace, the efficiency values are specified, but probably range from 70% to 90+%, and the source energy multiplier is low, natural gas being 1.047 and propane being 1.01. Therefore from a carbon footprint or fuel conservation point of view, burning the gaseous fuel in the fireplace is more than twice as efficient as usiing electricity to generate the heat. (80%/1.047)/30% = 2.5. As already pointed out, electric fireplaces are probably simpler, but they are poor from a fuel efficiency standpoint.

I am looking at it from the point of view of what it costs me. I don't mean to sound "non-green" but my concern is more what it will cost me, money wise, not how it impacts big gas companies or big electric companies. They have billions of dollars, I don't. I will utilize whatever fuel source costs me less money out of my pocket.

Lbear,
You need to do some serious calculations on the electrical consumption of all that geothermal equipment.
Your electric bill will be huge! And keep in mind, buried in the fine print is the "you have to have a back up heat source" clause!

Posted By sasanoa on 19 Dec 2011 08:26 AM
Lbear,
You need to do some serious calculations on the electrical consumption of all that geothermal equipment.
Your electric bill will be huge! And keep in mind, buried in the fine print is the "you have to have a back up heat source" clause!

I am NOT relying on the electric fireplaces as my primary heat source, they are secondary. The primary heat source would be a heat pump tied to a centralized forced-air system. I would also have in slab radiant floor heat. The fireplaces would be the last source of heat.

On a deep energy retrofit project I've been advising on we managed to reduce the design condition heat load to under 15KBTU/hr. The primary heating/cooling system is a 18K mini-split air source heat pump, and the "backup" is three plug-in oil-filled-radiator type space heaters. It's not completed yet- but I'm not anticipating huge electric bills.

An electric fireplace might serve the same purpose, but it's a much more expensive backup than a few space heaters. (I personally don't quite get the appeal of electric or gas fireplaces, but it's your house, your call.) You can get a lot more HEAT out of a gas or propane fireplace though, which may make it a more reasonable backup than an electric fireplace, depending on your actual heat loads.

In US climate zone 4 and the warmer edge of zone 5 a ductless mini-split air source heat pump can equal or exceed the whole-system efficiency of ducted geothermal systems at a fraction of the upfront cost and far less design risk. Before blowing huge wads of cash on geothermal it's usually worth comparing how much envelope upgrades in better air sealing, insulation & windows that would buy. In new construction it's often possible to bring the design loads under 2.5 tons and heat/cool with mini-splits, for less money up-front and yielding lower operating costs (due to both lower loads and higher average efficiency.)

For more money you can also run the slab radiant off a hydronic air source heat pumps at efficiencies similar to (or even better than) mini-splits, and that would still be less money than the same tonnage geo.

Much like radiant floor heating, fireplaces are hard to justify unless you have had one, it's about comfort. The intense heat source helps on those cold days.

I fortunately have radiant floor heating, a gas fireplace, a wood stove and a mini-split air-to-air heat pump here in Minneapolis. Since I use all these technologies and more in my
everyday design/build work, I would not give up any one. The total heat load is under 30mbtuh for 2200sq.ft., but each of the heat sources, wood stove, propane fireplace, electric boiler and air source
heat pump, can pull the entire load individually, save the passive solar aspects, including the attached hot house walkout level.

Each has its features and benefits which will vary depending on climate and local fuel markets. Naturally lifestyle plays a role in every heating
system design (after the math is done). As long as people know what they are getting, I am happy.

Ductless HVAC systems are kind of ugly, at least the ones I saw. In a 2-story home, one can run duct work inside the 2nd story floor joists, so there is no energy loss.

I think there is a line where it comes to enjoyment/aesthetics vs. best energy conservation. The best energy design might call for one to live in a 1,200 sqft box but people will not flock to that type of design. This is where one has to make that balance between energy conservation and design.

Yes and naturally there is the hiVeocity to consider. It is all about comfort. And one of our biggest challenges is still dealing with walls of glass. It is what makes life so interesting.

Merry Christmas to all

The indoor units on ductless system look like wall-warts to some, but you'll never achieve the same system efficiency with ducts, whether fully inside the thermal envelope of the house or not, due to significantly higher air-handler power use. It's not a minor difference, but the hit in efficiency can be reduced by going with slightly oversized ducts and continuously variable speed air handlers, as well as continuously-variable-speed scroll compressors. As a system the efficiencies peak when the air and compressor speeds are in the lower end of their range. Air handler power use increases exponentially (roughly 3rd power) with the air velocity in the ducts, and getting to break an average full system COP better than 2.0 in heating mode is no mean feat, whereas with decent ductless systems an average COP of 2.5 all but a given in US climate zone 5, and would be on the low side in zone 4.

It's usually possible to screen the ductless units from view in a high-R house with careful placement, making permanent valences to shield the view, etc., for the marginal functional downside of not being able to use the remote-control from across the room. The lower the overall U-values of the building envelope, the less it matters where you place the wall-warts, as long as there is reasonable air communication between the unit and the rest of the space, convection will distribute it sufficiently well.

BTW: Even PassiveHouse levels of energy use are achievable in AZ without resorting to living in a windowless cube. But the upfront cost of getting there is relatively high if doing it without higher-efficiency heat pump technology. The lifecycle of insulation is a lot longer than PV & heat pumps, but it's not always clear where to draw the line.

Morgan: About the fireplace thing- I have one, but (almost) never use it, but have given up trying to talk mi esposa on getting rid of it to be able to better insulate the house, gaining back some wall area. (I figured out early that getting rid of HER would make the place even LESS cozy. :-) The fireplace stays.) But then it's never as bitter-cold here or in Lbear's AZ than it is in the upper midwest. DO appreciate the comfort factor of radiant floors though, even during the shoulder seasons.

With a ductless system, one would have to punch an exterior hole in every wall, wherever they were located, right?

It's about a 3" hole, and you can seal up around it after the line sets go in.

That's right, about a 3" round hole where the line conduit enters the home (the unit doesn't have to be mounted on exterior walls, but it usually is.)

And it's possible to make them very air-tight- they are even found in homes that meet the PassiveHouse air-tightness standard ( < 0.6ACH/50 ).

For those who don't like wall mounted indoor units, Mitsubishi offers indoor units that can be mounted in the ceiling as part of their ductless system. It costs more.