The problem i have with this is everyone who says it has spent thousands on an mvhr system. I had one in our last place, the air was a lot drier (too dry really) and it was nice cleaning the filters and seeing all the muck its taking out the air. I'm not sure it was worth the investment. @joe90 used to turn his off in summer, @ToughButterCup hadn't bothered with one last time I heard and serial self builder @nod never bothers, but then his motives might be different! They are a nice to have and I will probably have one again in next place but I think you'd enjoy the comfort an aircon provides a lot more. How much would it be to first fix the pipes for the mvhr then make the decision later, the unit is usually the big ticket item but probably not if your having to pay labour on the install.