Well .. I just spent about an hour typing responses to all 15 ?'s adn lost it when I clicked spell check .. /forums/images/graemlins/mad.gif
Lets try again .. probably will be more brief this time though!
1. One zone or two? Depends on the size of the home, size of the zones and you budget. If its a very large home requiring over 4 tons of cooling you can cut energy costs by installing two systems and runnning only when needed. Zoning can be tricky and I've seen MANY more poorly installed zone systems then good ones. To operate well zones should be as close to 50/50 in load as possible. Ductwork to each zone should be oversized 25% to accomodate for when on e zone is closed. If the load is unproportaional (75/25 or so) then bypass duct, dump zone and/or freeze stat must be installed to prevent freeze-ups.
2. In my area of NY we have short coooling seasons (3 months or so) with days over 100* normally counted on one hand. There is no reteun on investment going to a two stage unit (used on 18+ SEER units) in my area. It generall costs $2000 additional for such an upgrade and it will not return in the life of teh equipment. AS of 1/1/06 the minimum SEER has been raised from 10 SEER to 13 SEER. Supopliers may no longer sell anything below 13SEER once they have depleated old stock. If you have long cooling season and expensive electricity it may be worth looking into.
3.A two stage thermostat is used to stage compressors.
Benefit of two stage unit is ablility to ad a humidistat and run in "dehumidify" mode
4. buy the most efficient boiler you can swing.. you can still add a temperature compensating control to drop boiler water temp and gain more efficiency. Ther is something to be said for the 80% boilers if fuel is cheap in your area (KISS theory) 80% boilers ternd to have less maintainence issues.
5. Buderus is the boiler of my choice. They make a new wall hung unit that is the cats meow ..although pricey! WeilMclean mades an adequate gas boiler (although I deplore the Gold series oil boilers the older blue series were much better) comparign the two is apples to bannanas though.
6.Towel warmers kick
a@$!! I have one in my master bath. You will probaly have to add a mixing valve to drop the water temp to it though 180* water will burn you if you touch the warmer. Min is VERY hot ... I run 165* water thru mine and it is very hot (my whole house is high temperature radiant heat)
7. Some kick heaters have 3 speed fans .. If you but a unit larger than required and run it at low speed it sould not be tto noisey ... GO FOR THE RADIANT IF YOU CAN SWING IT!!! You'll be sorry you did not do the entire house if you do!!
8. I've anly installed one fresh air unit in my life! I have little expertise to offer here.
9. Zoning a hydraunic unit is easy ... don't sell yourself short. May sure any area the may have "different" use is a seprate zone (Living area, formal dinind room, MBR, other BR, Bonus room over garage, basement, garage, etc).
10. You'll be very happy with an indirect6 HWH.. I have an Amtrol 40 Gal and have never run out of HW> Make sure your boiler is large enough to give you adequate capacity. I'm in oil heat territory and we can fire up the boiler easily just bey changing the nozzle. If you'r running a small boiler (under 100K) you may want to connsider an instantainuos water heater (rinai makes a great unit) which will also produce unlimited HW with not storage.
11. You'd have to drop the boiler water temp with a thermostatic bypass valve or a tempering valve (as mantioned previously). The valve mixes return water to the boiler with the supply water to the loop to drop the temperature. Depending on your construcion and radiant intall you may not have to drop the water temop too much. I have about 3600 sqft of staple up to the sub floortubing with reflective insulation below heting first and secondfloor. I have about 2600 sqft of basementy slab also heated. (over 10,000 feet of tubing) I rarely turn the basement on though ... its just plaly area for my children right now and it sucks up the oil when its running. I run my pex loops at 165* which is on the high end for radiant.
12. Theres lots of things I wish I coud afford ... heated toilet is not high on the list though /forums/images/graemlins/grin.gif
13. Skipped number just like a hotel!!
14. I too will only use sheetmetal duct systems. . I've removed too many duct board plenums that have deteriorated after years of use/abuse.
15. Yes, you can put heat/cool on one stat. The stat must have seperate cicrcuits for each. Most digital stats can accomodate this. There is a jumper between Rc and Rh that must be removed. This created two isolated circuits in the stat so that the transformers from teh boiler and air handler do not buck.
Lastly .. don't sell yourself short on teh comfort system ... you'll be living with the results for a lonf time. If possible look into a variable speed airhandler for the A/C...you'll be happy if you do choose such a system. The variable speed blower gradually ramps up to speed and down. the result is a sub-cooled col that removes 1/3 more himidity. It will usually add 1 SEER to a system. It also runs at 50% of full speed when the fan is in the on position and there is no call for cooling. It will filter very efficiently (buy a goood filter I use Spacegard) with reduced speed and only uses 60 watts of electric vrs. 4-600 watt that a convenetinal blower uses. Most of teh systems I install are variable speed. That upgrade is only several hundred dollars. ... Good luck ... Scozz