We are getting ready to bulid a 5000 sq ft home, and I'm getting advice from friends to do floor heating instead of usual blowing air heating, and to install tankless water heaters instead of regular water heaters. What is the difference in cost, and will I save money in the long run by saving on electric and gas bills?
Thanks-

Have you contacted a house designer to do your plans yet? (Not an architect who does banks) A 5k sf. Is fairly good size. As a residential designer myself, there are a few considerations for energy efficiency that need answers.
1. Is this home on a hill facing south is a good question for starts.
2. Is this a stick built design with a stemwall foundation?
3. Is this in the city or rural large acreage location?
4. Do you plan to incorporate less energy consuming equipment.
5. Any solar considerations.

This should be enough for starters. Nm:)

nmwirez Have you contacted a house designer to do your plans yet? (Not an architect who does banks) A 5k sf. Is fairly good size. As a residential designer myself, there are a few considerations for energy efficiency that need answers.
1. Is this home on a hill facing south is a good question for starts.
2. Is this a stick built design with a stemwall foundation?
3. Is this in the city or rural large acreage location?
4. Do you plan to incorporate less energy consuming equipment.
5. Any solar considerations.

This should be enough for starters. Nm

Thanks for the answer-
1- No hill
2- Have no idea what that means-
3- In a Chicago suburb on 1/2 acre
4- No idea
5- Not planning on solar, but certainly not against it. I hired a builder that does everything- designs, teardown, building, etc.

Thanks for the answer-
1- No hill
2- Have no idea what that means- This is not a slab floor and is 2x6 wood structure.
3- In a Chicago suburb on 1/2 acre
4- No idea Like hydronic heating from solar oven heater.5- Not planning on solar, but certainly not against it. I hired a builder that does everything- designs, teardown, building, etc.You have a set of plans then?
Sorry for those personal questions. Needed to know what you have to make reasonable answers as follows: (This is based on fair weather design with high efficiency construction in the area you are located.)
1. Instant demand heaters only work efficiently at short distances from the fixtures.
Central water heating with a Grundfas low energy pump will circulate and keep all faucets warm. Pipes need insulating and kept down to short distances to reduce loss.
2. Radiant floor heating is really a good way to go if the flooring is cement slab. This is a spendy propositions about 3 times more than a central forced air system.
3. There are combination boiler/domestic hot water gas supply setups that will also work with hydonic baseboard heat systems that are a little more efficient.
4. There is also New Heat radiant floor systems under vinyl or tile flooring that are not as good as the cement floor system because they do not have mass for retained heat.
5. Radiant heated floors may not be enough to maintain a house full of vaulted ceilings.

This should help... nm:)

The drawings are almost done, but only the layout plans- engineering plans have not been done yet.
It is not a slab- it is a very open floorplan over a basement- basement has 10 ft celings, main floor 10 ft ceilings, and upstairs 9 ft.
Main floor will be wood floors throughout.

The company that is building the house does a lot of homes in the high end suburbs, but I wouldn't say that they are using the latest high tech situations...
Thanks!!

I am not sure if a split system heat pump will be very efficient in your locality except for cooling in the summer. If there is a possible use of geothermal ground water heating, then the heat pump will work. This is very common in Canada. You have some space to do this. (22k sf-about a 2200sf footprint estimated.) nm:)

I want to point out a couple of things. If you are going to have A/C, you still need all the duct work that forced air heat needs.

Much to the dismay of those here selling and installing instant hot water heaters, I didn't like the numbers I came up with when I looked into one, and suggest others look before they buy. I couldn't see the amazing savings they claim. My summer gas usage including a gas dryer is less than what they claim a tank wastes. And as NM pointed out, instant hot water is only at the outlet of the tank. It takes just as long for the water to reach the end of a 25 foot run as from a tank. I will take NM's word they don't work with the recirculation system. I do know they specify a minimum flow to get any hot water at all. They may make more sense in new construction than a retro fit.

On both the heat and hot water, you need to talk to a couple of different people. Don't let anybody sell you a bunch of marketing hype. Ask questions and examine the answers.