A house without radiators...

"...

• inside temperature is homogenous; it is impossible to have single rooms (e.g. the sleeping rooms) at a different temperature from the rest of the house
• the temperature changes only very slowly - with ventilation and heating systems switched off, a passive house typically loses less than 0.5° centigrade per day (in winter)

..."

And for once, you can BUY one!! :D
Check this company: Scandinavian homes


And here you can see how they build these houses.

One of the key ingredients in passive houses are windows:
"...
Passive solar gain: The passive gain of incoming solar heat through the windows will cover close to 40% of the heat losses if all guidelines are followed. Optimised south facing glazing with none or minimal window openings to the north is a requisite. Most windows should be fixed as these have a higher performance than the opening type.
..."