Client got proposals for heating system. I’m trying to help him understand them and choose between proposals, one of which is a basic, low-cost system and the other of which is higher quality and higher price. I know some of what to look for, but not all. Just wanna give client some things to look for to decide if the higher quality is worth the extra money: capital cost, operating cost, reliability, comfort, etc.
System 1 is a high temp gas boiler, one pump, hePex, 3 zone valves w/ thermostat, backflow preventor, pressure regulator, expansion tank & air bleeder.
System 2 is a condensing boiler, 3 or 4 zones w/ separate pumps, controls, manifolds, hePex, backflow preventor, pressure regulator, expansion tank & air bleeder.
How would you suggest helping the client decide between these two setups?
Replies
not enough info. question... why not let the heating guy guide them? or are they like too many of my colleauges... the kind you don't want around your customer?
e-mail me and I'll send you my phone number. I would be happy to spend some time chatting with you about the different systems and giving you ideas on how to deal with this.
Gentlemen, don't forget to come back here with a synopsis. Please don't hold information hostage. Thanks.__________________________________________
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
I don't mind doing this online. What information is needed, Richard (WHW)? I'm looking for the theoretical approach on how one chooses between a condensing boiler and a traditional boiler, and one pump with tempered water v one pump per zone with more sophisticated controls. Don't expect anyone here to pick between the competing quotes. I won't give the prices quoted, out of respect for the contractors, but I'm assuming each priced it fairly, because I know the one and know he's the most honest person I know. I'll tell you any specs I know, be/c I designed the house. 2200 sf in a 3-part dome, plus 600 sf workshop in a separate dome. We've been averaging 12000 btu or less per 1500 sf in these, and no reason to expect this one is different. Climate is your general area, WHW--Pueblo. No unusual glazing. S-SW exposure for most of the glazing with limited N glazing, except where needed for egress. No A/C. Open terrain...no trees or impediments. What else would you need to know to lean toward one type of system versus another?
What are the floor coverings? tile, stained concrete, hardwood or carpet? What type of floor is it high mass concrete, low mass wood or medium - gypecrete overpour? Generally speaking the lower the supply temperature the more sense a condensing boiler makes. If the decision is made to go with a condensing boiler - I'd recommend a Viessmann Vitodense.
4" slab. Much tile with throw rugs here and there, some t&g (maybe bamboo), and little carpet. High efficiency building with exterior-insulated masonry walls & ceiling--definitely a high-mass house. A couple 10' x 5' windows on S-SW side. 2' deep overhangs. 35 degree average temp differential, so I know the guy doing the higher end system is worried about overshooting temps, and has included outdoor reset.
Go with the condensing boiler! The supply temps on this house are probably not going to be much above 90 degrees on a design degree day. Why heat the boiler up to 180 just to mix the temp back down to 90. Go with continuous circulation to constantly track outdoor temperature changes. You may need to have a slab sensor in the room with all the glass to keep the slab from getting to warm on a sunny day.
Here's my recommendation for the system. Use a Viessmann vitodense 8-32 modulating, sealed combustion, condensing boiler. Use Viessmanns low loss header to make the near boiler piping easy and compact, and use continuous circulation - that way you only need one circulator. The Viessmann Vitodense is the top of the line condensing boiler, it has a titanium stabalized stainless steel heat exchanger - it's the Mercedes Benz of boilers ( it should last forever). The Vitodense comes with its own built in controls, with outdoor reset built in, and it's virtually silent. The upfront wholesale cost of the Vito is probably twice that of a conventional boiler but, if you use the low loss header instead of constructing your own near boiler piping, the Vito will save time = $$$ - so the cost of an installed Vito comes out about the same as a conventional cast iron boiler with controls, custom near boiler piping, four way mixing valve, pressure bypass valve,multiple circulators, etc, etc, etc. The Vito gives it all to you in one neat small easy to design, install, troubleshoot and repair (should you ever need to) package - it's that good! No, I don't sell them - just a fan of the precise German technology. Post a question about the Vitodense on the WALL section of http://www.heatinghelp.com and prepare to hear it's praises sung.
I hope I've made your decision easier.
Thanks. I check this all out and share it with the customer.
Curious...with your familiarity with the field, have you ever seen/read Contracting Business magazine?
Over 40 years ago in a thermo class the prof told us that economics will change with time (gas was <7 cents gal without tax, NG only 2 cents/therm in some areas). His basic premise by laws of thermo was that condensing would win out when (no if, just when, wish I'd known his stock picks) oil (and NG, kWh, etc) were more pricey. Essentially concurs with others ops, condensing is the key word in the comparisons.
The debates about materials could go on forever. Each situation is different. A few things I stress when quoting a system are: Efficiency, Serviceability, and Quietness.
Efficiency: With more and more homeowners finishing off basements these days, I go with direct vent. This allows the boiler to be in it's own room and make-up air is not an issue. Also makes more sense to draw it from the outside rather than create a negative pressure on the building. Thus better efficiency.
Serviceability: Who's going to be servicing it? If it's the gas company, then ask for their recommendation. Where can I get parts in the future? Is the system going to be "service friendly"? I service what I sell, but I don't plan on being around forever. So I don't want to leave the customer with a dinosaur that parts are difficult to get or install it in such a way that nobody wants to service it. What's the warranty? It's mechanical, it will break down.
Quietness: Some units are quieter than others. Most of the noise is from the exhaust or fans. Pipes expanding, radiation creaking, air in pipes, velocity noise, and valves banging shut. Most are a product installation practices (again an endless subject). Sometimes the materials. Ask for references. Ask friends and neighbors.
Final Note: A heating system is not like a car that if you don't like it you can trade it in a few years later. You're stuck with it for twenty or thirty years. I tell people, "you might not know that I did a good job, but you'll certainly know if I do a poor one."
Good Luck
I would wonder about about system 1
Unless you have forgotten to list something I am curious how this high temp. non-condensing boiler system is going to work without a second circ. pump and either a mixing valve, diverting valve or injection pump ?
As a plg. & htg. contractor I bid against people bidding system 1 quite often. When I don't get the job I am usually contacted about 4 to 5 years later when the first boiler has failed due to flue gas condensation rotting out the heat exchanger. This is when the thrifty h/o realizes why the two original quotes were so different.
I would recommend system 2 from what I read in your post, especially if it is the Viessmann Vitodens boiler. We have installed a few now and they are an awesome boiler. I will post some pics later in the photo section of an installed Vitodens.
Edited 6/1/2003 12:03:41 PM ET by KC