Need some help with my Radiant Floor heat.

[got2lb]

I built a new house/garage last summer and am now checking into ways to get the infloor heat hooked up so it's ready to go by next winter.

I'll give some basic info first. House is located in Northern Iowa, Ranch style. House and Garage will have R60 blown in insulation in the attic. House and Garage are both 2x6 framing with R19 batted insulation. The Basement of the house is not finished yet but will be insulated. The slab was insulated with The 250 2" foam before it was poured. Garage slab was also insulated with the same foam and I also put it on the inside of the foundation walls down 4'. Garage is attached to the house. 2 garage doors 18x8 and 9x8 both are R19 doors, and the whole garage will be drywalled.

The basement has 9 loops for the floor heat around 300' each. It's roughly 2200 sq. ft. with a 9' ceiling. The garage has 5 loops around 300 ft each. The garage is 35'x36' with a 10' 6" ceiling.

Ok, so now how do I go about setting up a system for all this? Am I better off running each system separately or just the running the garage as it's own zone off the same heating source?

Now heating sources, I can run natural gas or electric. Right now the house is heated by a Natural gas furnace and I also added a Air/air heat pump. My utility company just told me since I have an Air/Air heat pump that I'll be getting a break on my electric for heating (not sure on rate yet), not sure if that makes a difference.

What should I heat it with? Boiler, Tankless water heater, or conventional water heater. I have a Rinnai tankless right now for my domestic water heater and I love it.

Ok I'm sure I forgot something but feel free to ask and I'll get you the answers. Would love to get the garage heated by next winter. The basement isn't finished yet anyway.

And a picture so you know what we're dealing with! Thanks in advance!

 

[anthony666]

ditch the tankless, install a combi unit, that will handle your dhw and heating

i'd seperate the garage with a heat exchanger and run glycol in there .. the rest of the house use water .. one system, primary secondary .. simple

 

[got2lb]

I'm not real sure what a combi unit is I guess. Could you post a link to something? I really hate to get rid of the water heater I just bought, it wasn't cheap.

 

[dieselgarage]

I like the siding on your house what do they call it?

 

[mygarageone]

I'm not real sure what a combi unit is I guess. Could you post a link to something? I really hate to get rid of the water heater I just bought, it wasn't cheap.

A combo unit takes care of your heating system and your domestic hot water needs with one unit. It a boiler and water htr built in one.

 

[Randy in Maine]

I have a combi boiler similar to this...

http://www.wallhungboilers.com/prod_baxi_condensing_380.html

Works well and is pretty efficient for my use.

 

[anthony666]

if you choose the right unit it'd be real simple swap, using the same venting and gas

 

[got2lb]

The siding looks a little goofy on the picture when viewing it on my phone, not sure why. It's just regular vinyl siding. It's Alside charter oak siding, I'd have to look it up again to find the name of the color.

What size of unit do you think I would need for all this? I suppose I could always sell my rinnai unit.

 

[michaeleagleton]

you should call a plumber.

 

[got2lb]

My brother in law is a plumber and hvac guy. He's the one that will be installing everything.

 

[mygarageone]

My brother in law is a plumber and hvac guy. He's the one that will be installing everything.

No offense but I wonder why you don't consult his advise about your system

I mean if this is what he does , wouldn't you want his opinion ?

 

[got2lb]

I do have his opinion. I like doing more research. I like having more than one opinion on things. Most of the people around here that have floor heat are either using a wood boiler or just a standard water heater.

 

[yeldogt]

So you don't have any radiant for the first floor?

If the basement is all underground you are not going to need a lot of BTU's for that space -- if you have a walkout you will need to split the system flow in the lower level to account for the differing loads

Radiant heat works best when it has constant circulation and an outdoor reset control - especially high mass concrete slabs -- all coupled to a boiler that can work with low water temperatures. You can set up other systems but it comes down to luck that they work as designed at various loads.

An example of luck: I have two sets of heated stairs -- each its own small loop. After we ran the house system for a while we needed to increase the water temp to both of those steps ... when I later added a small addition to the house using warmboard ... I discovered that the return temp from the steps was just what I needed for the warmboard -- so I just added the new loops onto the step returns.. it has worked great for four years now and saved me another set of controls.

You could have installed a gas boiler with an indirect WH and a hydrocoil in the air handler -- this would have then fed the radiant with normal controls.

 

[anthony666]

but it comes down to luck that they work as designed at various loads

so glad i wasted all those years at school .. please don't make ridiculous blanket statements if you have no idea what you're talking about

 

[got2lb]

There's no radiant on the main level and it's not a walkout basement. There's only one egress window in the basement and no other Windows.

 

[Highbeam]

There's always a little bit of luck involved.

 

[mygarageone]

There's always a little bit of luck involved.

How true that is , because I have seen some systems installed here that scares me but for some unknown reason they actually Work ?

I know if I did it that way , I would be sued !

 

[yeldogt]

Anthony666 -- I have no idea why you feel it necessary to make aggressive comments .. but it looks as if this is a common trait through many threads .. I also do not wish to discuss education.

Reading over many radiant threads -- people are satisfied with systems that "on paper" should not be performing ... and certainly not efficiently.. that was my point. You can't just throw pipe in the ground and connect it to a heat source and expect it to work ... but guess what ... some do just that and the systems work well enough that the owners are happy

A properly designed system will work .. and provide great comfort ...but I have also witnessed systems that should not work ,, and do.

 

[anthony666]

Anthony666 -- I have no idea why you feel it necessary to make aggressive comments

radiant heating is not the norm in north america .. it's still a surprisingly unknown entity to most folk .. a lot of my business is from people looking for an alternative to traditional, wasteful, quick & dirty forced air systems .. there are two categories of radiant clients, rich folk who do not care about the buy in, and the 99% who are going to go on the internet and research radiant before plunking down the hard earned cash on a pretty hefty investment

dude, i read your posts, most of the time i'm reasonably impressed with what you say .. they seem intelligent, well thought out and well meaning .. then out of the blue you say "but it comes down to luck that they work as designed at various loads" .. it's not luck .. it's the calculated delivery of the right amount of btus required, at the right delivery temperature over the correct amount of time to match a carefully calculated heat loss schedule .. i didn't learn this trade at hogwarts

you have no idea how often i have to spend hours explaining to people why they should invest their kids' college fund in a boiler over a way cheaper tankless water heater like the system they read about on the internet .. lemme tell ya, it's every single gig i do .. point is people read this and believe it like it's written in a trade journal so please be careful what you say

 

[yeldogt]

anthony666 ... I completely agree.

I did my first radiant back in 1983 using a Buderus Boiler/ Eccomatic and Buderus indirect. I have high heat radiant panels -- and various underfloor radiant ... it was expensive ... but has worked flawlessly and efficiently for 20 years ... I use this house as my office now. I have done radiant in every house since.

I agree the problem is that most don't want to spend the money -- and are looking for a cheaper way .... that was my point in saying ... basically .... well you can go ahead and try "whatever" ... but it is only luck that is going to make it work.

The example i referenced in one of my houses was not luck ... but I was lucky. I knew the temp of the returning water and I also understood that the added loop length was not greater then the pumps ... so I found an elegant solution to my problem.

It is very hard to tell people that the cheaper heat source -- not approved to be used as a boiler .. is not going to last .. and they will be buying another one ...... or that trying to heat a 6" slab in the morning after having it shut down all night is also not going to work ... at least not efficiently.

Years ago, one of the early radiant suppliers use a duel pipe and then a single pipe system .. it was not Pex ... they also recommended regular tank water heaters ... Not sure what failed first -- the pipe or the tanks .... but they worked great for a couple of years.

Trying to tell people: Don't burry pipe not approved for radiant heat --- and get the proper heat source.

With NG so cheap the last few years .. Some don't understand that the just installed system is not efficient.

People don't want to listen.

 

[mygarageone]

As professionals the net is the biggest thorn in our side , they the people believe everything they little beady eye see. Why ?
Because it's on the net don't y know ? As festis Hagen would say from gun smoke.

 

[SwampCat]

Ya ornery old skudder.

 

[got2lb]

I'm sure the professionals do hate the net. The problem I have with some of the places is that they try to push there product they sell even though it might not be the best solution. For me researching on the net it's no different than talking to multiple company's to get some different ideas on how they would do it and what it should cost.

Ex. When i had the plumbing rough in and finish quoted for the house one company was almost $10,000 and the one we went with was $4500. Why? Not sure. I live in a small community and sometimes the local guys don't think you'll call someone from another town I think to get a price. Concrete for the house was the same, I saved $15,000 for the exact same thing going out of town.

Like I said before most of the people around here with floor heat are using gas water heaters or outdoor wood boilers.

How much money does one of the combi boilers run? What size should I be looking for? Installation cost for me is $0 so that's a plus.

 

[anthony666]

I'm sure the professionals do hate the net

i dont hate the net at all .. i think its awesome, i grew up with a party line phone at the neighbors that the operator dialed and no tv .. information is great, disinformation *****

you ever watch a movie on tv, and they're welding for example .. or pretending to weld anyway .. i'm the guy screening at the tv screen that they're using the wrong rod, the polarity is wrong and with **** penetration like that it'll never last

i'm totally independent .. if i push a product it's because it works in my experience, not because they're sending me to the dominican if i get 20 guys to buy a boiler (i F##KING wish)

do a heat load calculation .. your brother in law can do that for you .. match the to the size of boiler .. there's leeway with a modulating machine, so you can go a bit bigger .. the smallest zone shouldn't be much less than 20% of the maximum output of the machine without some slick piping work

between 2 & 4 grand .. bro-in-law should be able to get 30 points off that