the rate affect of external temperatures and weather conditions on the internal atmosphere of a building is down to the details and method of construction. Its hard to regulate any heating system if you have a leaky badly insulated and constructed dwelling.
if you have a construction type that allows moisture ingress, or temperature transfer etc then external conditions will definitely affect internal conditions...
irish construction methods over the last 50 years have been far from adequate. they have been based on mass modular production with very little regard for the end-user habitation. cavity wall, cavity block and mass concrete building all have problems associated with their ability to restrict external weather conditions from affecting internal conditions.
to answer your question, if you build to such a level that the ability of external condtions to affect internal conditions are reduced tothir minimum, then you can quite easily regulate your heating system and have a good rate of control over it. This means having very good u values of elements of construction (walls, floors, roofs, windows, doors etc) in order to restrict teh rate of heat loss from internal to external as much as possible. Also, you need to have a building as air tight as possible to restrict undesigned air infiltration into your dwelling thereby sucking your much valued and expensive heat out.
in dwellings as described above, the ability to prevent over heating becomes more and more pertinent.... you may not think it in ireland but this is actually true. the first passive house in ireland had some over heating issues before the balconies were constructed, as far as im lead to believe. Therefore the ability to cool a house should also be consdiered in the design and construction. this can be assessed through use of passive ventilation methods and / or denser materials to absorb and store the heat until its required when the sun goes down...
iv eheard that it take people about a year to get to grips with teh setting of UFh and heat pumps etc. this to me sends alarm bells that the actual building i allowing external climate conditions to affect the internal microclimate way too much...