I'm in the process of building a house and want to put in a radiant system. Money is tight - very tight so I'm looking for ways to save a few bucks. I'm wondering if the heat diffusers need to be made of aluminum. I work driving an Amish pole barn crew so I can get left overs/scraps of the flat metal trim from the installs for free. Can these pieces of metal, called galvalum, be use for diffusing the heat from the pex tubing or does the diffuser need to be aluminum?

Good Afternoon folks, I'm not sure if this is a boiler issue but I have a feeling that it wouldn't happen with a hot water heater. The boiler seems to output a single temperature, just under 170 according to its dial. When I take a shower the position of the temperature dial seems relative. It takes it awhile to get hot (normal), and once it's set at a comfortable temperature, it slowly gets hotter and hotter until it's scolding hot. This happens without moving the dial. At this point I have to turn the dial down, usually it doesn't change the temperature (still scolding as it moves to the cold direction) until it's well within the cold region. At this point there's a dip in water pressure and the water turns instantly lukewarm or coldish. I then have to turn the dial back up towards the warm side and this process is repeated several times until I'm done cleansing. Is there a need for some kind of variable temperature controller on the boiler or does this happen because someone forgot to install a pressure stabilizing valve (I hear these exist)? We will likely be remodeling the bathroom so I might get access to the pipes back there to fix this. Unless, is this normal operating procedure for boiler-heated homes? Thanks for your help!