HVAC alternatives?

[RaT]

We are preparing to build a garage 34X44 with a guest house on top. The guest house will have a smaller footprint as it will be incorporated into the 12:12 roof structure with a couple of dormers for light and function. The whole thing will be under 1200 square feet and closer to 1000 sq ft. Rather then the expense of a ducted HVAC which would probably have to be sub'd out, have you an alternative idea that would incorporate non electric heat and also AC? I have thought about a couple of small AC units and then a couple of small radiators running off a boiler/domestic hot water as well but am tredding into unfamiliar territory. The idea of a couple of wall mount AC units is not real appealing appearance wise either at least fromk the outside. We will be living in this guest house as we then move our old mobile home and build a main house.

I would like to consider a hot water unit that will supply hot water for both buildings, the detached garage/guest house and the future main home. How about a unit that could supply hot water to both and also be used to heat the guest house? Am I simply looking at alternatives that in the end will be as costly as a central HVAC in the guest house? Thanks, RaT

[roho627]

HellO RaT, I 2 was looking for simular garage apartment type building for same purpose but never found floor plan that I liked! Haven't really investigated Air conditioner/heating system yet but would figure a heat pump with ducts run in ceiling of garage & vented throu floor would be good way to do it! I will keep up with U'r post to see how you go! What is schedule on construction! Mine is IF'Y cause Better half started back to RN Nursing School and it's takeing lots of effort to keep her Happy! KEEP Us informed on building schedule! roho

[RaT]

Roho, here is the link to the site where we first started thinking going with a garage / guest house. This is the model that more of less is what we are building. We did not buy their plan but drew up a modified version. Garage/guest house

Rat

[Pat]

There are alternatives to conventional freon systems for cooling a home. Most require relatively low relative humidity to work well. I'm not talking a conventional wall or roof mounted swamp box.

Aesthetics are acquired not innate qualities of judgement so some may like the following, some not. You can build a cooling tower system, essentially a couple large diameter chimneys, one on the south side of the house and one on the north. The one on the south side can be augmented with a wind scoop designed so that its aerodynamics keep it pointed downwind to serve as an exhaust system. The one on the north side can be augmented wit a scoop with aerodynamics to keep it pointed into the wind to develop a positive pressure. The north side chimney has evaporative pads in it fairly close to the top with a misting system to wet them. Some systems skip the pads and any maint associated with them and just spray the mist into the air inside the top of the chimney.

The misted air is heavier and subsides drawing in more fresh air to be misted and perpetuate the flow. Meanwhile the south side chimney provides a vacuum. The exhaust vents are placed near or on the ceiling to draw off the heated stale air. The cooled air requires large diameter ducts or typically a door between the main part of the house and the bottom of the north side chimney.

Works well in more arid regions.

Alternatively, pipes burried in the gound can serve as a source of cool air. as air is rdrawn into the house through the tubes it isi cooled. As this system does not require evaporation of water to provide "COOL" it will work in moist climates but not in tropical steambath climates as it does not do a great job of dehumidification (it can do some). With the cool tubes you need a means of drawing the fresh air in through those tubes. a south side chimney will do that. Properly sized and designed the chimney can do a credible job of sucking air without relying on a scoop or any wind. Build with substantial thermal mass, it will continue to function into the night.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[SLOBuds]

I think it is going to be difficult. The living unit is on your 2nd story. And I know that Sacramento is on the warm side. So everything is working against you.

My first recommendation is to insulate heavily. I would recommend that in any case. Insulate the roof of the structure, and insulate between garage and living quarters, and insulate the walls. There are different qualities relative to insulation. And there are toxicity issues that I suppose most folks don't pay much attention to.

I would not be surprised if you could use an R60 ceiling, and R30 walls.

It is much cheaper to apply insulation compared to installing and running devices which attempt to heat or chill rooms. This was a major 'ah-ha' experience for me during planning for my own new house. But it makes sense once you think about it. We naturally think about conditioning living spaces when, in fact, it is much more cost effective to prevent the ROOT CAUSES which call for those conditionings.

Windows should be double-paned casement, awning, or picture. On the inside of your windows should be curtains which have better insulating qualities - such as 'Duettes'. More effective than inside curtains are some type of window shield which you have OUTSIDE the widow. You may not care for the aesthetics of exterior window shades. But the heat reduction of exterior shades is much greater than reductions from interior shades.

In my case, where I am threatened with summer temperatures in the mid-teens, the exterior shades look JUST FINE. [img]/forums/images/icons/grin.gif[/img]

The best windows will only yield R values of 4. Or less. The best insulated window shades only provide that same R value. So windows are definitely the 'bad guy' for heat and cold transfer.

On the top of the peak of your living quarters, and towards the top of the garage, be sure to have a way for hot air to escape. Force the hot air out with a fan.

The garage fan should direct hot air away from the living quarters too.

I am not aware of night time temperatures in Sacramento. If it cools off during the night, then plan on ways to have windows open so that all of your interior thermal mass reduces temperature as quickly as possible. The fan which pushes out hot ceiling air should pull in the cool air.

On the 2nd floor like that, you probably cannot make too much use of thermal mass because of the imposed loads.

Pat's thoughts relative to in-ground tubing is good. There is a bit of engineering to accomplish with that solution, but most likely worth the effort. And ... I think it's low-tech enough for most of us to actuall do it ourselves. I would sink the tubes 4-6 feet into the ground, where the temperature is a constant 50 degrees.

I personally am going to make every attempt to minimize ducting to the highest extent possible. There are definite health issues related to ducting. But I just can't see a way around using SOME (it may be unhealthy to have moldy ducts in your house, but it's probably even MORE unhealty to not remove stale and moist air from inside the living quarters!)

So you will probably end up with tubes here and there inside the walls. I'm planning on filters at all ends, plus regular and religious cleaning.

Your location sounds like mine. I will have a more difficult time keeping the place cool in summer, compared with the effort to keep it warm in winter.

Radiant floor heating is the way to go for the winter (if needed at all because of your super-insulation!).

Again, even after all of these steps, you might be challenged to get that above-garage house cool enough for comfort. Without air conditioning that is. But it is an attractive structure and I'll bet you will be able to have future revenue off of it. Also, if you do need auxiliary cooling, it will definitely be minized by all of these other actions.

So best of luck!

Martin

[CJDave]

[img]/forums/images/icons/tongue.gif[/img] This is what I would do if I was building in the Sacto area: I would use liquid THERMAL STORAGE which was big enough to make it through one of those long, hot, summer days in Sacto. I would set it up so that I could cool the liquid down to near freezing AT NIGHT with my compressors/condensors taking full advantage of the cold night air, AND maybe even get a Time-Of-Use electric meter to get a break on the price because I was using OFF-PEAK POWER. Inside, I would cool with individual room coils and coil fans with a thermostat in each room that started and stopped the fan. In the winter I would use a tankless hot water heater to heat the loop. [img]/forums/images/icons/tongue.gif[/img] One of the hospitals in Turlock installed a Thermal Storage Unit several years ago and quit running the A/C units during daylight hours. They used a Eutectic fluid of some kind that was supposedly twice the capability of water. [img]/forums/images/icons/tongue.gif[/img]

[SLOBuds]

CJDave,

Could you elaborate on 2 questions?

Where do you achieve cost savings using this method, and, how is the resultant moisture handled? (Moisture is our enemy!)

[img]/forums/images/icons/smile.gif[/img]

Martin

[CJDave]

[img]/forums/images/icons/tongue.gif[/img] In Sacto, and in most of California, electricity is fairly expensive. By using a Time-Of-Use meter and using the majority of your power in Off-Peak hours, you become a friend of the power company and there are rewards for that. The summer in Sacto is dry enough that condensate would not be a big problem......well under five gallons per day.... in winter on those really foggy days you should still be OK with the hot water heat, since you can run the piping at a fairly high temperature. There is a big motel not far from you.....it's over by Cal Expo somewhere on the freeway to Reno.....that uses a four-pipe system, two for hot and two for cold, and they seem to be fine with regards to moisture. THE BIG ADVANTAGE to HVAC systems that use THERMAL STORAGE is that they don't have to use 110-degree air to cool the coils on the condensors which is a joke and a waste of power. At night the compressor will use MUCH less power to do the same job. AND......you can pipe this same system to the new diggings when you build. Make it such that you can easily add to the thermal storage tank when the time comes. [img]/forums/images/icons/smile.gif[/img]

[RaT]

Very interesting. I don't know that PG&E does time of use metering for residential customers, they do for solar or eNet customers. I know that they do for commercial high rise. I am good friends who managed some of the ones in downtown Sacramento. Heating is no problem but cooling is an issue. Much of the cooling is done at night in the off peak hours. I get little fog up here in Aubrun, we are at about 1000' while Sacramento is close to sea level. Electricity in California, at least with PG&E is not really out of line with other states, it's the stinking distribution and transmission costs that adds up. They actually break it out for us. I think our summer humidity is typically about 35%.

PS, what part of Kalifornia did you live in? [img]/forums/images/icons/grin.gif[/img]

[CJDave]

[img]/forums/images/icons/tongue.gif[/img] We owned a home in Modesto and we owned a home in Mi-Wuk Village....in the Sonora Pass Vacationland. We actually lived full time in the We-wook house at 4500 feet elev. We sold both houses in '01 and bought this little farmette in Iowa. It was always my intention to do the thermal storage trick; either on my Modesto home or on the Mi-Wuk house; so I could cool with cheaper off-peak power after I retired, but the political climate more than the actual climate made us decide to get the h#ll out of a state where I was a fourth generation native. Our humidity in Mi-Wuk was about 25% give or take. I think that Auburn would be an ideal location for a thermal storage system.....it has everything that you need in terms of heat, cold, and humidity. I cannot recall, do you have natural gas there in A-Burn? [img]/forums/images/icons/crazy.gif[/img]