ᐅ What installation spacing should be used for radiant floor cooling?

SandyBlack schrieb:

@11ant you mentioned the entire planning process. That also includes the heating system. Unfortunately, your other statement doesn’t help me much. Could you specify what the catastrophic consequences of the planning are?

Whatever this "other statement" might be, I never said there was a "catastrophic plan," we probably just misunderstood each other.

SandyBlack schrieb:

I am fully aware that the planning has significant room for improvement. But this improvement always tends toward enabling lower supply temperatures for heating and possibly a slightly better cooling effect. If you see any other disadvantages caused by this plan, I would really appreciate if you could explain them.

Let’s start fresh—I think there has been some confusion.

So, the intention is to install a radiant floor heating system with cooling function—ONE system that provides both heating and cooling, not separate heating AND cooling systems. This means there is only ONE circuit / medium. And logically, only ONE pipe spacing—the spacing cannot simply be switched between "heating" (heat emission) and "cooling" (heat absorption).

Let’s assume the user wants different responsiveness for heating and cooling—to have one function operate "faster" or with less lag. The same medium, same pipe length, and same pipe spacing density are all fixed within this single circuit. Within this framework, switching between "(forward) heating" and "cooling = reverse heating" modes could only be done by offering either different output through unequal floor area or by changing the pump speed to shift "gears."

Now, consider the case where the cooling function is perceived as too slow on a network designed for heating. In cooling mode, either the flow rate in this network must be increased, or additional cooling surface is needed, which can then be added as a "turbo mode." The most practical solution would probably be a radiant floor system optimized for heating with regular pipe spacing for normal operation, plus an additional cooling surface, such as ceiling cooling—perhaps above the seating area, dining table, or near the kitchen exhaust hood. I do not see other practical approaches to the wishful idea of magically adjustable pipe spacing—somewhere, the luxury has to remain affordable.

To summarize: if you want to cool "faster" than you can heat with a dual-function system, you need either a variable flow rate of the same transport medium or a larger cooling surface compared to the heating surface—in other words, an additional ceiling cooling surface is required in cooling mode.

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RotorMotor schrieb:

Well, I’ve seen worse calculations. The only obvious problem here is the bathroom again.
Not just the pipe spacing, but especially the circuit length. Over 100 meters (330 feet) in the bathroom is really not good.
The 150W underperformance is already noted and is probably even higher in reality.
At least divide it into two circuits. That only costs an extra valve.

How does it look in the shower/toilet room downstairs? That looks catastrophically short...

We have planned an additional infrared heater on the bathroom ceiling. It only has 700 watts (700 watts), but it should hopefully be enough. We also wanted to split the heating circuits, but the general contractor is relying again on the manufacturer, who says heating circuits including the supply line can be up to 120 meters (394 feet) long. Including the area under the bathtub, we are at 117 meters (384 feet). However, I will bring this up again.

The shower/toilet on the ground floor is only 42 meters (138 feet) in length. The room is very small, only 3.3 meters (11 feet). There, we will install a mirror with integrated infrared heating.

@11ant We really crossed wires here. Your comments

11ant schrieb:

The "construction" shown in the plans seems to me like a fool’s errand / a prank close to the Flat Earth Theory *LOL* [...]

11ant schrieb:

[...] Regarding question 1, I seriously wonder – quite concerned – how much of the general education that was still common "in my time" must have been lost to develop a plan like this at all, without realizing what one must have been smoking *shakes head*

were addressed to our underfloor heating design in general. I do understand your point that heating via underfloor systems combined with cooling via ceilings is a much more sensible solution. Unfortunately, I am not aware of any ceiling cooling options for wooden ceilings.

SandyBlack schrieb:

...
regarding our general underfloor heating planning. I understand your point that heating via underfloor heating and cooling through the ceiling is a much more sensible solution. Unfortunately, I am not aware of any ceiling cooling options for wooden ceilings.

There are cooling sails that can be hung below the ceiling. They can also be designed attractively, for example as artwork or decorative objects.

And please don’t dismiss it purely based on financial payback. If you want the comfort of efficient cooling and it costs around 2,000 (for a lifetime of extra luxury), then go for it if you can afford it. Otherwise, you might just skip one holiday trip.

P.S.: With an air-to-water heat pump, cooling requires additional electricity, while a ground-source (or brine-to-water) heat pump can provide passive cooling down to about 3°C (37°F). That’s how I had my wall heating system designed, which can also cool—just not both at the same time. It worked quite well during last summer’s heat. If you want more cooling capacity, you’ll probably need an air conditioning unit because lowering the temperature further is eventually not possible due to condensation.

SandyBlack schrieb:

I understand your point that heating through underfloor heating and cooling through the ceiling is a much more sensible solution.

No, I suggested both heating and cooling through the underfloor heating system, with additional cooling surfaces to cover peak cooling demands. To avoid competing for floor space (and because cold air tends to sink), I proposed placing this second "heating-cooling circuit," which is only activated in cooling mode, on the ceiling.

SandyBlack schrieb:

However, I am not aware of any ceiling cooling option for timber ceilings.

It must exist, though. As far as I know, the timber prefab builder Huf equipped a project in Montabaur consisting of several residential and office multi-family buildings with such a system.

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i_b_n_a_n schrieb:

There are chilled ceiling panels that can be suspended from the ceiling. They also come in "attractive" designs, like artwork or decorative objects.

Thanks for the info, I didn’t know that. Until now, I had only seen such solutions used in industrial settings. I’ll look into it. But I assume these systems also require water circulation and are therefore difficult to retrofit, right?

i_b_n_a_n schrieb:

And please don’t exclude it just because of the financial payback. If you want the comfort of efficient cooling and it costs 2k (for a “lifetime” of extra luxury), then do it if you can afford it. Otherwise, just skip a vacation once in a while.

The payback calculation only referred to heating costs. If I had the option to invest 2k to significantly improve cooling efficiency, I would do it. But I don’t really see that option. Even if we reduced the installation spacing to 10cm (5 inches) everywhere, the effect on cooling through the underfloor system would probably be limited.

@11ant Understood – thanks 🙂

I am quite certain that 15cm (6 inches) or 10cm (4 inches) won’t make a difference when it comes to cooling.
Floor coverings could be an issue. With our glued vinyl flooring, 15cm (6 inches) works perfectly.

The bigger problem with cooling using radiant floor heating is almost always moisture over time.
This doesn’t improve if you include walls and ceilings.

Efficiency is much less critical for cooling than for heating. Cooling is needed far less often, and usually, there is enough photovoltaic electricity available.
So make sure you can split the circuit in the bathroom.
Don’t hesitate to spend money on this. You’re building a house for a lot of money, and it should work well for many years.