Talk:Water heating

T&P Valve

T&P Valve - does it ever need replacement?

If it breaks, yes. Carcharoth 07:06, 17 August 2006 (UTC)

Tankless more efficient?

The topic of tankless efficiency came up, I did some numbers:

I have a 130L tank. It is heated to 50C. The water comes in at 15C and needs 19MJ to fill. It is wrapped in R3 insulation with a surface area of 1.5m so it loses 0.5W per delta deg C. Thus it loses 17W of heat when hot. That's 13 days worth of storage equivalent to 1 heating cycle.

Where do people get the efficiency claim from? Tankless water heater manufacturers? --njh 00:07, 15 March 2006 (UTC)

R-3 is about 2.5W m^-2 K^-1, so your tank will be losing 1.5*2.5*(50 - 18) = 120W, not 17W. This maps to 2 days, not 13. So if you use 1 tank/day, then over 2 days you heat three tanks, efficiency is about 70% of a tankless solution. As you use less water, tankless systems become even "more efficient". As you use more water, efficiency equalizes, but then a tank becomes increasingly pointless... mdf 14:58, 14 July 2006 (UTC)

For US residents, tankless is sometimes less efficient. Centralized tankless may result in more water use due to it taking longer for the water to get hot. It may also result in more water use due to the greater availability of endless hot water. In any event, tankless in the US often costs more for the heater and more for the installation. They are more complex and less common, and so cost more to maintain. So even if there were an advantage in efficiency or cost, it might not be enough to ever get "paid back" over the life of the installation. Most support for tankless seems to come from those who make and sell them, and people who think the idea sounds great. But researching actual experiences of users reveals many problems. (R-3 sounds like a very minimal level of insulation for a tank.) 69.87.204.237 16:23, 16 November 2006 (UTC)

Tankless is either more or less efficient, and this is decided on physical principles, not where one lives. Money, logistics, the consequences of a failure, and the like are important, but unreleated matters re: thermal efficiency (the subject of this section). mdf 21:28, 24 November 2006 (UTC)

And of course, people who make and sell water tanks are selfless dedicates who would never consider, even briefly, promoting their schemes for merely pecuniary purposes. mdf 21:28, 24 November 2006 (UTC)

R-6 seems to be the least tank insulation common in the US. 69.87.193.102 13:56, 17 November 2006 (UTC)

Going from R-3 to R-6 goes from 2 days to 4 days in the above example, and you've hit ~80% of a tankless's thermal efficiency (everything else held the same). To hit 90%, we need to go to R-12. I've always wondered why just about everything made in North America -- houses, cars, water tanks, etc -- are woefully inefficient. Why not just wrap the tanks in R-20 or more insulation and be done with it? Ah, the Mysteries of the Market ... mdf 21:28, 24 November 2006 (UTC)

Anode rod?

Should the article mention the sacrificial anode rod?

Yes. Also unions, fill and drain valves, sedimentation and periodic flushing (tank-type), costs, typical lives, etc. Keep writing!  :-) 129.237.114.171 14:24, 25 October 2006 (UTC)

Getting the anode rod out in a typical old installation in a utility closet, without breaking something, can be very hard! We need some good advice. 69.87.200.214 02:12, 18 November 2006 (UTC)

Wikipedia isn't a how-to site. You can find DIY and repair advice at other sites with your favorite search engine. —Quicksilver^{T @} 22:59, 16 December 2006 (UTC)

photos

Since this is something that does vary a lot around the world, it would be great to have lots of photos, showing typical installations in many different countries. 69.87.200.214 02:09, 18 November 2006 (UTC)

Tankless Water Heater Info

This website has made a video and has a couple of guides about water heaters.

http://www.plumbersurplus.com/videos/Tankless-Water-Heater-Buying-Guide/1 --Masterplumbersocal 16:36, 11 January 2007 (UTC)