Note:
This article will not attempt to make an installer out of a DIYer. A
reputable HVAC company hires knowledgeable technicians who are up to
date with their education as well as having experience in the field. This can be a very dangerous attempt if you don't have some basic HVAC knowledge, i.e., more than just watching a few y videos! Why put your family at risk to save a few $$ or to stroke your ego?
Can a DIY successfully (and safely!) install a replacement hot water heating boiler? Yes and No....depending upon many factors, (e.g., do you have the mechanical skills, proper tools, testing tools, soldering skills, know where to look for information or who to ask, being familiar with local codes, perhaps some ancillary experience like a code or house inspector, HVAC assistant helper. ...), to name a few.
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| Planning a Boiler Replacement |
Perhaps you have no intention of actually installing your boiler, but just want to better understand the sales talk. There is a link at the end of this article that will show many steps of an actual install, and will give you an idea of some prices on parts to be used on the project.
Just to be clear, we are not talking about a water heater for your shower and washing dishes, although there are some combo boilers that supply both heating and domestic hot water.
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| Water Heater for shower, washing, ... |
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| Boiler Combo |
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| Hot Water for Heating |
The photo immediately above is the type of heating boiler that provides heat for the house through radiators, baseboard radiators, or radiant floor heating. When the original heating system was designed/installed, the installer/contractor allegedly performed a heating load calculation to calculate the Btu requirement to adequately keep the house at the desired temperature. Unfortunately, some may have used their "WAG or mind" calculator, or even worse, sold the owner the size they happened to have in their inventory. I like to think that most companies are honest.
Since this article is about a replacement piece of equipment, the DIYer needs to be aware that some changes may have taken place over the years since the original "calculations" were made, e.g., better insulated windows installed, more insulation added, additional space added. So you cannot assume the original calculation (if actually performed!) is still valid, particularly since the new equipment you want to install should be more efficient.
Of course, you can search the Internet for all kinds of free information on load calculations and free load calculators. You can use your current boiler as a starting point, although it probably will be oversized, especially if it is over 30 years old. Another way to get a possible size (measured by Btu), is to use the figures from the three estimates that you got when you were planning on having a reputable company install your new boiler.
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| Page from Manual J Worksheet |
The three estimates should be relatively close, as far as Btu calculations (using Manual J or a similar formula). The total price estimates may be far apart, depending on many factors, including what "new" items are included in the price and what current items might be reused.
I am sure your original intentions were to select one of them, and you were just pricing things out while checking out their sales pitch/promises😀. Pay particular attention to the estimator that actually walked with you through your house and jotted down some info.
In defense of the HVAC sales person, they know you may be just wasting their time looking to get a low estimate from several contractors, so you can "understand" why they might not want to do a full thorough calculation. Actually, some of them are pretty good at "ball-parking" Btu sizing.
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| Goldilocks and the Three Boilers |
You need to decide if this is good enough and if you are willing to gamble on your boiler being oversized/undersized or just right! After you finish reading this article and the link to an actual installation, you may want one of them to do the work!😐
As far as the actual installation, since this is replacement, you already have the old system to copy...assuming that it was installed correctly. You can plan your modifications (like adding an air separator to replace the old air scoop) on paper beforehand. But be aware, sometimes things look good on paper but aren't practical in a real install, e.g., that existing pipe or wiring that gets in the way of your new plan.
See an Actual Install>>> Boiler Install
