Radiant in little used space? How to control?

Weezbo

if you go in for cathedral ceilings consider a radiant beam:)

foam every outside "corner" put insulation down on the flat around the perimeter, around the perimeter oblique to that along the foundation , insulation around the exterior walls ,have the insulation blown in the 2X6 exterior walls ,...pay close attention to the vapor barrier sealing everything , use electrical boxes that seal,designe your trusses on the place for insulation and Ventilation over the exterior walls...seriously consider an HRV or ERV, forget carpet, run two loops instead of one in a room :) insulate beneath the SOG insulate beneath the floors, consider sound insulation ,...think more insulation in the lid....triple pane windows...insulate around windows and doors .......what was the question?

Luke Lefever_3

How to control little used radiant space?

We are putting together an estimate for a large new house that will be built on a sand dune overlooking Lake Michigan. This would be used only as a weekend house or a couple of weeks during the summer. What should we be suggesting for a control strategy that'll bring it up to temp in advance of occupancy? I'm thinking about something from Tekmar tn4 that allows remote control through an ip address. With so much thermal mass (it'll be Gypcrete pour) I'm wondering how other guys have handled situations like this. We could put hydro-coils in the air handlers to warm the air quickly, or we could do programmable thermostats that begin warming up on Thursday night in anticipation of Friday occupancy. Do we space the loops a little closer to get more BTU per square foot?

Surely some of you guys have insight to share here.

Thanks, Luke Lefever, Lefever Plumbing & Heating, Inc., Elkhart, IN, www.lefeverph.com

Uni R_3

High Mass Retreat Home

It sounds like your clients need a very responsive HVAC system. To me the most efficient way would be to keep the internal mass low so the house warms quicker using far less energy.

With high internal mass, it's kind of like having a big battery and by the time it's fully charged and the temps have all evened out it's Sunday and everybody's heading home and all that stored energy ends up being wasted until it's mostly depleted by the following Thursday and then boom, it's recharge time again.

I would think that mass in conditioned spaces should really match the intended usage. If people will be there 7/24 and you want steady temps then mass is great, but for houses that will vary their temps, mass just makes them less responsive. You can still have radiant floor heating without the gypcrete.

hr

medium mass system

is what I consider a 1-1/2" gyp pour. Not quite as slow as a slab on grade to respond. I feel gyp systems respond near as fast as under floor dry systems, especially with tight tube space as you indicated.

Depending on how complicated you want to get, yes you could us a phone dial up to start the system.

Or put the floors on an outdoor reset with a slab sensor to idle them at a low (not to exceed) temperature.

hot rod

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Kevin_54

Boiler choice

Have you thought about your boiler? You should check out Viessmann and their Vitotronic controls, it sounds like a perfect fit. It also sounds like a high-end vacation type home you are quoting so the upgrade to a Viessmann should not be a problem. Let me just say that i am not a Viessman rep i'm just a fan. They will also help with your engineering questions and possibly help with your design.

Glenn Sossin_2

Lowest possible mass

I would think the lowest mass system would be best. Why spend time heating the house/floors when he's not there, taking hours longer to get up to interior design temps? I agree with Uni R.

Luke indicates its a weekend home. The HO decision to go there or not go there may be made on the fly. With a low mass system, the heat energy pumped in would be transfered to the surrounding structure more quickly than a high mass system. This way, the house is potentially heated when the HO gets there.

I agree with HR about the phone dial up. The TN4 internet gateway is not available yet. I was just at another Tekmar seminar a couple of weeks ago. Randy indicated it might be a few more months before its available. Even when it does come out, it apparently will go into the hands of a few select reps/distributors. I'm hoping I'm one. I've got 2 jobs in process where this gateway has been requested by the homeowner and a 3rd were about to start.

Luke could still do TN4 and have remote telephone access, and add the internet gateway at a later time. This would allow the homeowner to monitor the status of the house no matter where he is provide he has access to the internet. According to Randy,if theres a problem, the system can send out an email to notify whom ever he progams into the gateway.

If he has a home on the lake, I would guess there will be a large amount of glass facing the water. If he has a fair amount of solar gain, perhaps he could consider injection with a constant circulation secondary loop. This way, the solar gain could be tranferred to other areas of the house - in essence, some free heat coming from the higher mass floor assuming its gypsum.

If this is the case Luke, this approach can also help your AC system by moving the heat gain to other areas of the house making the AC system more comfortable, easier to control. If you really want to get fancy, you could put in a 3 way valve, hooking up your floor to fin tube or a toe kick heater , and discharge the heat outside the structure, helping to reduce the AC load.

Honeywell just came out with a new control system. VERY SHARP LOOKING. Similar to Tekmar with option of scenes for heating and AC, etc. There was supposedly a conference call today for Reps only where they were announcing new modules including injection. They too have the remote phone access.

hr

maybe radiant isn't right

for this entire home?

Panel rads sure are quick and very comfortable. Consider a mix of radiant floors in the baths, possibly kitchen and panel rads on TRVs elsewhere.

Gyp at a remote lake location sounds expensive? Spend the money on hybrid hydronics and insulation instead.

Best of all worlds. Clean, quiet, quick responding, efficient, DHW compatiable... a showcase job in the works

hot rod

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Tombig_2

Two stage

> for this entire home?

>

> Panel rads sure are

> quick and very comfortable. Consider a mix of

> radiant floors in the baths, possibly kitchen and

> panel rads on TRVs elsewhere.

>

> Gyp at a remote

> lake location sounds expensive? Spend the money

> on hybrid hydronics and insulation

> instead.

>

> Best of all worlds. Clean, quiet,

> quick responding, efficient, DHW compatiable... a

> showcase job in the works

>

> hot rod

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 144&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

Tombig_2

Two Stage

Through the winter months they'll have to maintain a minimum temperature for antifreeze protection. If they've got some sensitive finishes in the house they might want to maintain a little higher "away" temp. Your gyp pour will also help for those occasional winter power outages along with Weezbo's insulation schedule.

Second stage hydro coils or, even simpler and cheaper, electric strip heaters in your air handlers, will bring the space up to temp quick. By the time your client gets from Elkhart to Michiana, or wherever, the system will be settling into warm floor territory.

Except for "high flywheel effect" rooms (by the way, solar gain is free) I think concrete or gyp is the best delivery system for what we're selling. If you're installing air handlers for summertime AC anyway, second stage a scorched air delivery that will jump start the house.

I'm in the process of installing my first Tn4. I've heard that some complaints are that second stage pulls in to soon. For this application this is desirable. Tekmar has two stage Tn4 stats available with single stage cooling. Work out the telephone/PC interface and you're there.

Good luck Luke, sounds like a nice job

Tom Goebig

singh

weekenders

I'm in a spot where 90% of my clients are second home owners. So I'm very interested in the great responses so far.
I've used the tekmar 545 stat 2H 1 cool. Many scenes to bring up temps at expected arrival. The second stage is fan coil for quick recovery.
I hope tekmar comes out with the internet based module soon.

I've also been looking into control4 systems, and proliphix systems.
www.control4.com
www.proliphix.com

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Tombig_2

Quick warm up

In my area we can easily see 45* at night in the middle of summer and up to 95* in two days. Summer/winter switches are too unwieldly for most consumers so I opt for stage two "quick heat". At first I balked because I didn't want to pull in the radiant at all. Unless someone has a simple solution to this problem, that's my story and I'm sticking to it.

Uni R_3

Tom, this is where mass can help...

High external mass is ideal for wide daily variations. You just have to keep the mass outside the insulation high and inside the insulation low to keep the responsiveness.

6 - 8" thick concrete walls, a 4" sealed XPS layer and then woodframe construction all inside the shell. Same deal on the basement floor (high density under ply subfloor) with routered in radiant in baths and key areas. The rest oversized TRVd panels or CIrads. Try and design for a single supply temp. That to me would be a sweet efficient design. You could even just use a programmable t-stat that has dial up support. No waiting for tekmar and no need for tn4, although tn4 would be fun for the fussy.