Hello, We are looking at poss. upgrading our heating system in the next year or so. We have microbore pipework. We have been given a couple of quotes for a 16KW air source heat pump. I was a bit unsure that this would work ok with microbore, both companies quoting said it would be ok - they would install another pump to keep the water flowing. Does anyone have any experince of ashp's? It is a lot of money if we go ahead - maybe we should stick with oil and go for a condensing / unvented cylinder (we have a combi currently). Thanks