Towel radiator at low flow temperature

In recent months, we have always assumed that we would install a towel radiator (HTHK) with a heating cartridge in both bathrooms. Yesterday, we spoke for the first time with our heating installer. He said that the positions we had considered were very unfavorable. In the small bathroom, he saw potential problems with a rusting HTHK. Basically, he saw issues with the power outlet being in the splash area. He saw no problems with HTHKs that are fed by our ground source heat pump with correspondingly low flow temperatures. He said that in summer it would be quite low, e.g., 35°C, and in winter higher, e.g., 45°C.

There is underfloor heating throughout the house.

Bathroom 1:
HTHK between shower exit and bathtub
Bathroom 2:
HTHK opposite the shower

Now to my questions:
1. Can HTHKs be hung upside down?
2. Can HTHKs (with appropriate wall penetrations) be plugged into a socket in the adjacent room (utility room)?
3. Does an HTHK work properly at low flow temperatures?
4. Can HTHKs rust?
5. Is an HTHK necessary? The heating capacity from the floor area is sufficient for both bathrooms. There is talk of transitional periods, but doesn’t my bathroom always have its 23°C when I set it?
6. Don’t towels dry without a heating function?

We have towel radiators in the main bathroom and guest bathroom, both operated via the underfloor heating and both get warm, not boiling hot like at 65 °C flow temperature but completely sufficient to dry towels or as "auxiliary heating".

Many questions to which I have no answers.

How many square meters do the bathrooms have?
We do not have any additional heating or towel warmers in our bathrooms.

Our guest WC, with about 5 sqm, also has heating coils under the shower, so the room is nice and warm - in the off-season we do not heat, it is sufficiently tempered.
What I want to say: Your floor areas seem sufficient to me if the heating coils are laid densely as standard and also in the shower.
Personally, I like towel warmers, but we were told that technically it is not easy because of the heating circuits... so we don’t have any. Also, they warm the towels and not the room!!!

Towels dry with us also on a bar and also over a chair.
An alternative heating option would be infrared heaters: they are supposed to heat the room faster and effectively for a short duration - just google it.
With 4 people, drying towels might not go so quickly, so a towel warmer in the main bathroom would be an advantage. I believe I have seen them mounted upside down, but I’m unfortunately not sure.
But for the socket, it would be a good alternative for you, since it can then be installed outside the splash area.

To make sure whether these units can be mounted upside down, I recommend checking Google images with exactly these heaters and seeing if any are hanging the other way around.

Hi,
I would consider the position uncritical. However, a fixed, splash-proof wiring should be provided instead of the socket.
But I would just hang it on the heater anyway. We currently run between 35 and 40 degrees flow temperature in winter, which is completely sufficient for the radiators. They are set to level 5 and that’s fine.

Even if you will have lower flow temperatures with the geothermal heat pump (which I suspect), it should still have an effect.

I have never understood the argument that it wouldn’t get warm in the bathroom during the transitional period without the heating cartridges. Yes, then the heating just stays on! You’re not installing a geothermal heat pump in your house for a ton of money only to heat with an immersion heater!?!?

Best regards,

Andreas

Necessary in the sense of "necessary to get the bathroom why" the HTHK at our place are not either. But a very nice comfort for relatively manageable additional costs.
Warm towels are something nice!

And they are also the only places in the house where we can quickly dry wet gloves and generally wet clothes in winter. That is worth a lot!

Best regards,

Andreas

I have never understood the argument that without the heating cartridges in the bathroom it wouldn’t get warm during the transitional period. Yes, then just leave the heating on! You don’t install a geothermal heat pump in your house for a ton of money only to heat with an immersion heater!?!?

I don’t understand that either. I also like it warm, but I’ve never been cold in summer. If it should be really cold in September, then I just turn on the heating. However, the house is well insulated, so it can withstand several days of cold.