Replies

1. 
   TJK1141 | Apr 10, 2005 09:29pm | #1

   I personally don't like the idea of a dual-use system where the potable water ties into the hydronic plumbing. On older systems, you really don't know what chemicals might have been in the hydronic lines, and there is no way to use glycol for freeze protection in harsh climates. A heat exchanger would deal with that issue, but at higher installed cost and less efficiency.

   Modern boilers have modulating gas valves and can vary the heat input to match the load. Water heaters typically have bang-bang controls that are inherently less efficient.

   The big downside for boilers is their higher installed cost. I suspect that in many cases it might make sense to use a plain ol' tank water heater, especially if fuel costs are reasonable, and the climate is mild.

1. 
   RBean | Apr 11, 2005 02:04am | #2

   The majority of professionals would agree with you.  As Dave Yates pointed out in the article - residual chemicals from an old system or tank is a real possibility.<!----><!---->

   Your comments and comments from many others is why we introduced the Farm Team - Pro Team analogy to HVAC and in particular to radiant systems...in other words if building homes was a sports league complete with amateurs, farm teams and professionals, it would be difficult if not impossible to win a professional tournament with a farm team or amateur approach.  I would suggest it’s the number one cause of consumer dissatisfaction with the housing industry. That doesn’t mean the amateurs or farm team players can’t win…they can and do win by playing in their league of competencies.  The professionals do not tolerate the mistakes and bad habits found in the lower tiers.  Excuse the cliché but they have been there and done that and have moved up or out.  For example, a professional would do a heat loss and gain calculation on every project and match the systems to the loads.  An amateur would say it worked on his/her last project so it should work on every project.  The pro’s got to be pro’s by the pain they experienced as they moved up through the league.  They don’t want to go through it again and it frustrates the heck out of them when they see the farm team and amateurs make the same mistakes they made early.  Why? Because many amateurs and farm team players are vying for their jobs and often do amateur and farm team things to get the work.  Unfortunately when consumers expect pro’s but get amateurs or farm team players it often leads to misery.  It happens all the time when its one thing to spend 5% of the construction cost on HVAC for heating and cooling (survival needs) and another to spend 15% for health, wellness and comfort or “total well being” needs.  When there is a failure in survival systems people die. When there is a failure in “well being” needs people get miserable.  This is one of the reasons why over 50% of North American’s are unhappy with their HVAC systems - people thought they were getting comfort but what they got was a survival product.  (ref.: ASHRAE, Honeywell and Decisions Analysts) It's one of the reasons why we see a need for “environmental ergonomists” or “thermal environmental comfort technicians”. 

   When we stop thinking that we are supposed to heat/cool buildings and start believing that we condition people we’ll see a greater disparity between those who heat (survival) with water heaters and those who condition(well being) with boilers.  <!---->

   Deep eh?

   RBean

   http://www.healthyheating.com

   http://www.healthyheating.com/blog

    

    

   Edited 4/10/2005 9:43 pm ET by RB