Water collector for the toilet is build into the wall...
In my case, there's a 2m wide, ~70cm deep space behind the bathroom, where the water + heating + sewage + ventilation pipes for the whole building are located. There's a 40cm access panel in my wall to get to it.
Adding a bidet thing would require drilling a hole through the wall.
A previous apartment had a similar toilet, but the tank etc was just hidden behind wooden panelling. That would be much easier to modify.
[1] https://i.ebayimg.com/images/g/fFAAAOSwnhNdyM2F/s-l1600.jpg
Most these attachments connect to the toilet's water supply, which is fine, except most toilet water supplies only provide cold (i.e. whatever the ambient water temperature happens to be) water which to me, is far from ideal in a bidet (it's fine for normal use though).
Running hot water there is a significant undertaking if done correctly, so most options come with a small reservoir to heat up water from the regular toilet supply.
That heat isn't magical, it needs energy from somewhere meaning you need to run power there someway.
There are dangerous improvised solutions like running a power cable yourself. There's additional consideration electricians put in when installing power in restrooms due to all the water and grounding dangers from metal plumbing. Running cables neglects all that thought and reintroduces an electrocution hazard if not handled very carefully.
That leaves me with battery options which I haven't looked to much into but I find that's likely not ideal to swap batteries around all the time. If it can operate off something like a deep cycle marine battery (which seems appropriate), then it might be viable.
https://www.homedepot.com/p/Leviton-15-Amp-125-Volt-Combo-Se...
Couldn't find them in Canada though. Had to buy from USA.
Now my toothbrush can charge for more than 5 minutes a day (the lamp had a socket on it, but again, wouldn't want to use that for a bidet!)
I guess you might not have this if you live somewhere like west Texas.
In my old rental, the mixing valve malfunctioned and condensation was causing damage to the floor. In my current house, it mixes in too much hot water. If you flush a few times in a row, you can feel the warmth off the toilet bowl. It needs to be replaced, because it doesn't have an adjustment screw.
Searching for the condensation problem in Britain, plumbers suggest using an insulated cistern (tank).
I've never heard of an insulated toilet tank over here. I wouldn't be surprised if they start showing up, though.
My current house was built in the 80s, when the region was flush with oil money. I get the impression that building anything energy efficient was seen as a political statement, aside from the added cost to the builder.
During the winter its a bit colder but still nothing like the well water back in the midwest. Well water bidet would cause hypothermia to your anus
Well, if you have a reservoir before the bidet, it'll get from ambient water temperature to ambient air temperature if it sits long enough. How many litres does a bidet use at a time? Nowhere to slot a 2L reservoir?
Getting the water to 22C should be far more tolerable than the 5-8C many of us are used to in winter.