Getting silly with energy savings...

[Firethorn]

For anybody who hasn't figured it out, I have something of an interesting upbringing.  The son of two accountants, I do cost-benefit analysis as a matter of course.  On the other hand, I'm a major techie.  I find any technology, even 'green' technology, interesting.  But I want it to be cost effective; especially if it lacks suitably awesome side effects.

For example, Solar panels and wind turbines are neat, but in the end they simply produce electricity.  Solar/heat pump/geothermal heat is also neat, but only heat. 

Anyways...  When I start thinking about my dream home I tend to think less about the color and fittings of the house than all the 'neat' stuff I want to put in.  Still, any modification from 'standard', in the end, has to be justifiable.

But - In order to determine if any given improvement is financially worth it/effective, you need to at least consider it.  So by all means, let me know what I could do to save energy, or otherwise have a 'neat' house!

Initial Thoughts on construction:

I want a Foyer/cloak room area - Reason being, the semi-isolated area reduces hot/cool air loss when entering/exiting the building.  Bonus - Good spot to leave the bulky northern coats and snowy/muddy boots.
Basement is a requirement.  If it ends up in a suitably hilly area, a half basement would be fine and nice.  I'd be shooting for 'semi-finished'.

Massive construction - I've read nothing but good things about having a home with a good deal of thermal mass to the walls.  They help moderate temperatures and prevent you from wanting the heating system on at night and the AC during the day.  Insulation, lots of it, covering the TM on the outside, before whatever siding material is used.  You want a material that isn't too conductive to heat, but still has a lot of mass.  Concrete and dirt are frequent choices.
Extreme option:  Underground home - but that carries a raftload of it's own problems.

Network connections - I'll have almost as many of these as the home has electrical outlets.  At this time, cat-6, but run in conduit to ease pulling new wires if, for example, fiber becomes the next big thing for some reason.  All terminating in a patch panel/rack somewhere in the house.

Heat(house/water):  Various options:
Solar heat - better the further south you go. 
Heat pump - requires electricity, can also cool.  Can't, however, heat during the coldest weather when it's needed the most, and is fairly expensive.
Geothermal - better than a standard heatpump, but even more expensive.
Wood/Coal - Back to traditions; increased maintenance requirements.

Electricity:
Solar - Expensive enough that cost of capital would generally more than pay your electric bills, even with subsidies.  Still, can be mounted on a roof fairly easily.
Wind - Small turbines are less efficient cost wise; lower altitudes from shorter towers reduce availability of ideal wind.  Not all areas are windy enough.  Neighbors are likely to object to the big turbine sitting up on a tower.

Cooling:
Use heat from solar thermal panels and a variation of Einstein's refridgeration method to cool your house(look up absorption chillers), or at least your refridgerator/freezer.  If your house, it has the bonus of providing the most cooling when your house generally needs it the most - those hot, sunny days.  Depending on the exact temperatures, it even means you can use those solar thermal panels/tubes that are otherwise sitting idle to provide the heat. 

Misc:
Heat pump water heater.  Retrofits onto existing electric heater and cools/dehumidifies your basement while heating the water in the tank.
Heat pump clothes dryer:  From readings, drys clothes faster without needing an air exhaust or heating the clothes up as much.   Some implementations also known as 'dehumidifyer dryers'.  Uses about a third to a quarter the electricity vs a electric dryer.  Can be 110V vs 220V.

What do you think of these?  Any neat home energy stuff you can think of?

[zahc]

I don't know about all that, except I would run Cat5 everywhere. But I've been reading some stuff about straw-bale construction that really has me interested. I can't get over the pest, rot, and the possibility of it being huffed, puffed, and blown down by a big bad wolf, but none of those are supposed to be problems. It just seems like it would be a rat heaven. I wonder if it only works in desert-type climates, and not cold wet Ohio ones.

[Firethorn]

I don't know about all that, except I would run Cat5 everywhere.

I'm doing you one better, cat-6 in conduit.

But I've been reading some stuff about straw-bale construction that really has me interested. I can't get over the pest, rot, and the possibility of it being huffed, puffed, and blown down by a big bad wolf, but none of those are supposed to be problems. It just seems like it would be a rat heaven. I wonder if it only works in desert-type climates, and not cold wet Ohio ones.

From my reading, they mostly propose this in texas; so a dryer climate may be assumed.  From reading, the reason pests aren't really a problem is that by the time you compress and plaster the bales, there's not enough oxygen for pests to become an issue.  Same deal with fire.  As for blowing it down, well, it ends up being substantially more massive than a traditional wall of the same cross-section, and it's reinforced with wood, bamboo, or steel stakes in addition to the adobe.

Still, very neat idea.

[zahc]

Actually, perhaps because I was a total basement-dweller growing up, I think the ultimate would be an underground house. I doesn't get more energy-efficient than that. I used to deliver pizza to some people with an underground house. One day when I went there a deer was eating their roof.

[Balog]

Underfloor heating is considerably more efficient than traditional.

[Firethorn]

Actually, perhaps because I was a total basement-dweller growing up, I think the ultimate would be an underground house. I doesn't get more energy-efficient than that. I used to deliver pizza to some people with an underground house. One day when I went there a deer was eating their roof.

Don't you mean eating on their roof?  There is roof structure under there somewhere...

Potential problems with a underground house include difficulties in providing enough exits, the need for artificial lighting in the deeper rooms(or light pipe towers), condensation, water leaks, etc...

I figure that a suitably massive house can give you most of the benefits without the downsides.

Underfloor heating is considerably more efficient than traditional.

Can you use the same pipes for cooling as well, without making the floor so cold that people make undesirable comments?  Thanks for pointing it out, I'd forgotten to mention it.

[Manedwolf]

Underground house, another problem.

Radon.

[Ron]

great topic! been thinking about this a lot lately

I want the option of having fireplaces and wood stoves in strategic locations, even if I have a typical system for normal use.

+1 on the radiant floor heat.

There is a solar a/c system I ran across that runs during the day. The cooling coil is not a coil but a loop around the ceiling with a drip pan. The refrigerated pipe looped around the room causes cooler air to fall down to the living space.  At night you can only utilize ceiling fans running off batteries.

It was being used on tropical islands where there is no grid at all.

[HankB]

Scot Adams used to have Dilbert's Ultimate House on-line, but it seems to have been removed. A pity . . . I suspect it would have had much of what you want.

[Brad Johnson]

Easiest way to get lots of mass is to use insulated concrete forms.  Four to six inches of reinforced concrete with two inches of polystyrene foam on either side.  It's like living in a bank vault.  A side benefit is the home is also severe weather resistant.

Zoned HVAC.  Not single-compressor-with-damplers zoned, either.  True seperate units for things like main living area and kitchen, master bedroom, etc.  This allows you to completely close off parts of the house not in use, keeping them at a reasonable maintenance temp until needed.

Also, no two-story.  And no ceilings over 10'.  8' is even better.  Less volume, less to heat and cool.

More insulation in your attic.  A lot more.  About 60% of the heat migration in most homes is through the ceiling/attic.  12" minimum.  14-16" recommended.  It's the single cheapest energy saver you can buy.  And insulate your interior walls.  It will help reduce heat migration in the home, especially if you have zoned systems.  It will also help with noise attenuation.

Plenty of attic ventilation and some auxiliary attic fans.  Keeps heat buildup to a minimum in summer, ice dams to a minimum in winter.

Also, for wiring, espceially data, phone, and TV... run everything to a common point.  Don't daisy chain.  Set aside an area in a closet/gargage/basement for all the runs to meet.  Run phone and data stuff from a punchdown block and patch panel.  Terminate all the TV cable runs with standard connectors and configure using distribution blocks.  It may sound a little extreme, but it gives you complete control over future configurability.

Fireplaces are great but they are horribly inefficient.  Most of the heat goes up the chimney.  You can recover some with a heatilator.  A stove is much better.

Electric heat is, by definition, almost 100% efficient.  But electricity can be costly.  Weigh the cost of gas vs electric in your area and choose accordingly.

As for solar panels, maybe.  New techonologies are just around the corner that will bring down the cost per Kw dramatically.  There's also the option of a couple of small wind turbines (by small I'm talking about 4-6' rotor sizes) but even those don't come cheap.  I'd be tempted to set up your wiring for an auxiliary source, but wait on choosing which kind to use to see what the prices are going to do over the next few years.

Brad

[K Frame]

Better still is one of the European style thermal mass stove/fireplace units.

Amazingly efficient.

[Balog]

Better still is one of the European style thermal mass stove/fireplace units.

Amazingly efficient.

Is there a way to vent the heat from that to an underfloor heating arrangement? I know most modern systems are water based, but if the Romans could do it....


As for cooling, if you aren't in a super hot climate, have massive well insulated walls, and give a little thought to the design cooling needs should be neglible. Have a gander at the way homes in hot climates were designed pre-air conditioning.

[K Frame]

The Roman hypocaust heating system was incredibly fuel inefficient.

[Balog]

The Roman hypocaust heating system was incredibly fuel inefficient.

I don't understand why a properly constructed, modern version would need to be though. Combine a lower level high mass stove, with a way of force ventilating some of the air through sub-floor vents.

Of course, water is always a better means of heat transfer. Perhaps a closed loop heating coil warmed by the thermal mass stove?

Even if not used for sub-floor heating, would putting the thermal mass stove on a lower level be a good idea? Any safety issues?

[Ron]

How about sharing links to any of these alternative ideas and technologies?

[Nick1911]

I think you'll find that many of these cool new technologies aren't economically viable when you start getting price quotes.

[K Frame]

My music teacher in high school built a house on a very large chunk of wooded land that was given to him by his grandparents.

One of the big features was a VERY large, very heavily constructed fireplace that had vertical stainless steel pipes lining the flue.

In those pipes were finned copper pipes connected to two heavily insulated tanks filled with an anti-freeze solution that served as the primary heat retainer for the baseboard heat throughout the house.

Another, smaller, loop, heated the house's hot water.

The combination of the hot water and the thermal mass from the fireplace stack (he said the contractor estimated its weight at better than 50 tons) kept the house very comfortable in all but the coldest weather. When it got really cold out they had a wood stove in the rec room that provided additional heat.  

At the time I didn't know crap about thermal mass fireplaces other than that many of the older homes where I grew up had enormous chimney stacks. Obviously they were designed to be thermal radiators.

A chimney stack that large needs a LOT of support, so it has to start on the lowest level of the house and be built up from there.

[Firethorn]

As for cooling, if you aren't in a super hot climate, have massive well insulated walls, and give a little thought to the design cooling needs should be neglible. Have a gander at the way homes in hot climates were designed pre-air conditioning.

Part of the reason I'd have a basement and use massive construction.  Right now I'm keeping it a tad generic; but one thing I've said in the past is that homes should be built substantially different in New England over Florida.

Of course, water is always a better means of heat transfer. Perhaps a closed loop heating coil warmed by the thermal mass stove?

As long as we're being silly, how about having the high mass stove/fireplace include cooling channels that, with a few valves, can have the central heating system route it's water through for extra or even primary heat?

I'm thinking it could be done with two valves, or one diverter - Either the water is diverted through the stove or not.  As long as we're being fancy, we could even automate it by having some sort of temperature control.  Stove hot, diverter sends the water through the stove.  Cold, it bypasses.

Even if not used for sub-floor heating, would putting the thermal mass stove on a lower level be a good idea? Any safety issues?

It was done all the time back in the day, and safely as well.  You just have to pay attention to the chimney and fireproofing. 

Easiest way to get lots of mass is to use insulated concrete forms.  Four to six inches of reinforced concrete with two inches of polystyrene foam on either side.  It's like living in a bank vault.  A side benefit is the home is also severe weather resistant.

I like this.

Zoned HVAC.  Not single-compressor-with-damplers zoned, either.  True seperate units for things like main living area and kitchen, master bedroom, etc.  This allows you to completely close off parts of the house not in use, keeping them at a reasonable maintenance temp until needed.

Wouldn't this be too expensive, especially if our home building processes result in a house that's not very expensive to heat/cool in the first place?

Also, no two-story.  And no ceilings over 10'.  8' is even better.  Less volume, less to heat and cool.

While I can agree on the somewhat lower ceilings, isn't two stories a GOOD idea from an energy standpoint for a given square footage of house?

IE a 10 meter by 40 meter house becomes a 10 meter by 20 two story house.  Assuming a 3 meter story height:
400 square meters of floorspace, but the two story only has 200 square meters of roof.
1 Story:  300 square meters of siding 2 Story: 360 square meters. 
Total outside surface area: 700 M^2 vs 560 M^2, most of the savings in the roof, as you say, the biggest loss point

Also, for wiring, espceially data, phone, and TV... run everything to a common point.  Don't daisy chain.  Set aside an area in a closet/gargage/basement for all the runs to meet.  Run phone and data stuff from a punchdown block and patch panel.  Terminate all the TV cable runs with standard connectors and configure using distribution blocks.  It may sound a little extreme, but it gives you complete control over future configurability.

Agreed

I think you'll find that many of these cool new technologies aren't economically viable when you start getting price quotes.

Agreed, which is why I mentioned 'cost effective' in there.  Still, I'm a techie, and it's neat stuff. 

[Brad Johnson]

Also, no two-story.  And no ceilings over 10'.  8' is even better.  Less volume, less to heat and cool.

While I can agree on the somewhat lower ceilings, isn't two stories a GOOD idea from an energy standpoint for a given square footage of house?

IE a 10 meter by 40 meter house becomes a 10 meter by 20 two story house.  Assuming a 3 meter story height:
400 square meters of floorspace, but the two story only has 200 square meters of roof.
1 Story:  300 square meters of siding 2 Story: 360 square meters. 
Total outside surface area: 700 M^2 vs 560 M^2, most of the savings in the roof, as you say, the biggest loss

The only way to make the equation work is to insulate and airtight the structure between levels.  Heat migration (up in winter, down in summer) changes the load on a given level.

Winter example, closing off the upstairs to save money.  Good in concept, but heat will migrate from the lower level through the uninsulated floor/ceiling barrier at a frightening rate.  It would be the same effect as having no insulation in the ceiling of a single-story structure.  It can cost 50%-70% more to heat a lower level if the upper level is unheated and the structure between is uninsulated.  Heat migration up uninsulated interior walls can easily add another 10-20% loss.

I have seen the difference in a very literal sense.  Two 2-story houses, built side-by-side, same plan.  They are identical right down to the paint color except the buyer on one home insisted that the structure between the levels be filled with insulation. (contractor = grumble, grumble, grumble...).

I toured the homes as the finishing touches were being applied.  Said grumbly contractor pulled me aside and said, "Hey, you need to see this."  He had the thermostats in both houses set at the same temp, and had the houses configured the same (shades drawn, upstairs closed off, second level HVAC off, etc).  He had load meters on both houses, showing how the first floor HVAC compressor had been cycling.  The house with the insulation between levels had about a 20% duty cycle.  The house wihout the insulation was seeing about a 30% cycle.  The unit was having to run 50% more all because of the heat migration through the uninsulated structure between levels.

Brad

[Headless Thompson Gunner]

I think you'll find that many of these cool new technologies aren't economically viable when you start getting price quotes.

That.  Many of these fringe technologies would be mainstream if this were not the case.

[Firethorn]

Winter example, closing off the upstairs to save money.  Good in concept, but heat will migrate from the lower level through the uninsulated floor/ceiling barrier at a frightening rate.  It would be the same effect as having no insulation in the ceiling of a single-story structure.  It can cost 50%-70% more to heat a lower level if the upper level is unheated and the structure between is uninsulated.  Heat migration up uninsulated interior walls can easily add another 10-20% loss.

What if you're NOT closing off the upstairs because, well, you LIVE up there?  Then the fact that the heat migrates upstairs, while needing compensation for when the building is designed, isn't actually costing you any energy since the upstairs needs to be heated anyways.  If we're looking at radient floor heating and forced air for cooling anyways, that's where we could have the sectioned air systems.

He had the thermostats in both houses set at the same temp, and had the houses configured the same (shades drawn, upstairs closed off, second level HVAC off, etc).  He had load meters on both houses, showing how the first floor HVAC compressor had been cycling.  The house with the insulation between levels had about a 20% duty cycle.  The house wihout the insulation was seeing about a 30% cycle.  The unit was having to run 50% more all because of the heat migration through the uninsulated structure between levels.

upstairs closed off...  Well, of course it's going to take more cooling for the one with no insulation between floors when you're trying to not condition one of the floors.  What would happen if you did another experiment; say turn the HVAC on for both houses...  I'm willing to bet at that point the insualtion between floors wouldn't do much for energy savings.

To expand on this, you'd get the same deal with your 1 story zoned HVAC - better have the interior walls between zones insulated.

Insualtion between floors would be a good thing anyways; for sound if nothing else.  Heck, I'd insulate inner walls somewhat for that reason.  I do agree with you on the roof insulation, of course.  I'd have so much you'd be measuring it in feet, starting with 3'.  My parents had that much cellulose insulation blown in, essentially costing them any attic storage, but it paid off in heating and cooling bills in 2 years.  Our house would still have snow on it when it had already melted off of everybody else's.

[Bogie]

I used to know some folks who had their whole family living in what they called "The Compound." Grandparents, the three families, etc... Four different houses, and a large shop building. Supplemental, sometimes primary heat was a large external wood-fired boiler, with insulated underground loops to the houses and shop. And road/driveway... They'd fill it in the evening, maybe in the morning.
 

[Brad Johnson]

upstairs closed off...  Well, of course it's going to take more cooling for the one with no insulation between floors when you're trying to not condition one of the floors.  What would happen if you did another experiment; say turn the HVAC on for both houses...  I'm willing to bet at that point the insualtion between floors wouldn't do much for energy savings.

Even if the entire house is open and used, you're still going to run into issues with the upstairs because it will not only be getting heat from the exterior walls, it will also be getting waste heat from below.  However, there is an offset in that the heated air from below is being replaced by cool air from above.  Simple convection will result in the lower level seeing a lower heat load than the upstairs area.  The net effect is that the upstairs A/C unit needs to be a little oversize while the downstairs unit can be slightly undersized.  HVAC contractors should be calculating for this though many, unfortunately, don't.  (Maybe 280plus will drop by and fill us in on the details.  He probably has a spiffy calculation for determing unit sizing and ariflow balance issues with multi-story structures.)

It really all still boils down to how well the exterior is sealed and insulated.  Solid walls, plenty of attic insulation (including insulation sprayed in under the decking), and decent windows and doors make the single story/two story debate kinda moot, especially if you have have the thermal mass to really stabilize interior temps.

Here's one a lot of people don't think about.  If your roof is composition then use the whitest shingles you could find.  I think white shingles are ugly as sin, but the temp diff in an attic can be as much as fifty or sixty degrees for dark shingles vs light.

[Headless Thompson Gunner]

Here's one a lot of people don't think about.  If your roof is composition then use the whitest shingles you could find.  I think white shingles are ugly as sin, but the temp diff in an attic change by as much as fifty or sixty degrees for dark shingles vs light.

I've seen some light colored steel roofs that were no hotter than the outside temperature.  Solar reflectivity makes a huge difference.

[Brad Johnson]

Yep.  A steel roof over an inch of high density foam works pretty well at keeping things relatively cool.  Makes it quieter, too. (A steel roof in a Texas hailstorm can be a bit noisy.)

Brad