I had bad experience with high efficiency Triangle Tube Prestige Solo (399,000 btu). It was installed in 2008 in my new home (then under construction) at my plumber's advice. big mistake! I should have gone with Buderus that my architect had proposed (more expensive but supposedly very reliable) or with some other, like Lochinvar (which would cost me $1000 less than Prestige). There was a problem almost from the start when we had a short power outage in town and the unit shot down and wouldn't restart, and I had to call my contractor to get it going again (after finding out in the morning there was no hot water). Then there was another shotdown a year after we moved in. This time, standard resuscitation procedure didn't help. The Triangle Tube rep at the customer service phone line was extremely unhelpful – borderline rude – and made it kind of clear the customer service is really not for hoi polloi, only for esteemed bona fide professionals. Curiously, the rep mistakenly thought the problem was with the defective control panel ' he admitted they'd had many issues with it and had a recent recall but they still wouldn't replace it for me at no charge! Eventually my plumber had to spend two days first trying to figure out the problem and then fixing it. As it turned out the blower (brand new, bought with the system) went bust. That was for no good reason, since the boiler room is all tiled and surgically clean, with no dust at all. Then I learned they only give warranty for 1 year which is a scam since it always takes a long time to finish the new house and move in after the boiler is delivered, so they really cover it for just a few months at best. And no one ever offered me to buy an extended warranty. Now I had to cough up $1500 full price for the new blower (additional to the plumber's fee) – they knew they had me and didn't even have courtesy to offer a discount. Phone calls to the warranty dept at Triangle Tube went nowhere as they won't lower themselves to talking with an individual customer, warranty department is really not for that in their view. A rep from their distributor's company where I had to buy the new blower promised to talk with the 'right people' at Triangle Tube and take care of the cost of the blower (especially since I tried to be nice and gave them the old unit so they could look into what went wrong), but instead he simply wasted my time and eventually wouldn't answer the phone or return the calls. So Triangle Tube has now zero prestige in my book, my advice is, go with someone else. Btw I since have found other complaints about them on the internet, wish I'd looked earlier!