Here are the proper steps to designing an efficient and cost effective heating system:
1. Through in depth discussions with the GC and building owner, determine exactly what the building owner expects from the new heating system - what type of system will it be? There are numerous options for system types and the type of fuel it will utilize. What level of efficiency will the system be capable of? What level of equipment quality is expected? How many heating zones are desired? How will potable water will be heated - through the boiler and indirect-fired water heater, or a separate heating source like a direct-fired water heater - gas, electric, oil, or solar? In the case of an "indirect" water heater, I will be sure to add the requisite BTUs per hour for the domestic hot water as needed. Basically, all relevant information will need to be conveyed with person-to-person discussions, and the HVAC subcontractor should be able to drive the discussions to the point that all questions will be satisfactorily be answered so he can proceed to the next step.
2. The HVAC sub needs to obtain a complete set of working construction drawings that include all floor plans, elevations drawings, window, door and insulation schedules, and geographical orientation.
3. The HVAC designer will then interpret the drawings and harvest all of the necessary data from it to be used in the heat loss calculation software. The software will tell him how many BTUs/hour the building will require on the coldest day and will break the total down by individual room "loads".
4. The designer will then select the proper equipment based on fuel type, "net" heating output capacity (in BTUs/hour) and how the heating appliance will be vented - through a chimney, sidewall-vented or power-vented out the side of the building or direct-vented through the roof. He will also account for quality and efficiency rating.
5. Then the heat distribution aspect of the design will be worked through. For FHW, he will determine pipe sizing and type, circulator (the 'pump' that moves hot water from the boiler to the terminal units) performance characteristics, flow control devices and terminal unit type(s) and sizes.
6. The designer will then choose the control systems based on number of zones, energy-savings and safety and code requirements.
7. The fuel storage type and capacity will be selected.
8. A total cost estimate will be generated and a proposal listing all of the major components will be drafted and submitted.
This is a basic list of steps. In reality, there are so many details to creating a competent design and estimate that delineating all of them goes beyond the scope of this article. The most important point is that the heat loss calculation must be competently performed before any other design step can be taken. The other important thing is that the proper equipment be selected that answers to the heat loss calculation. If the equipment heating capacity is guessed at, then the system will most likely be over-sized...for the life of the system. Next is as important - the efficiency of the equipment is crucial to future fuel consumption and a true professional HVAC system designer will promote the highest efficiency available. Spending a few hundred dollars initially is always more advantageous financially than forever burning more fuel due to poor efficiency. Consider higher efficiency equipment as an investment in future fuel savings.
If any of the steps outlined above are skipped, then greater operating and service costs will result. Some HVAC subs do not design the systems they install, their equipment/parts suppliers do the calculations for him and he automatically believes they did the calculations right. Often a lot of rounding up gets done in the HVAC design world, as nobody wants to be left holding the bag if too small a system is installed, then doesn't sufficiently heat the house on the coldest days of the year. And that rounding can account for 25% of the system capacity - it will be too over-sized and cost the building owner more money to heat.
I can't express enough how many HVAC systems are incorrectly sized and designed. I see them every week I am out in the field. It is more normal for systems to be designed incorrectly than to be designed correctly. Yes, I repeat: most heating systems are designed incorrectly and burn too much fuel!
While plumbers and HVAC companies are often incompetently designing and installing heating systems, fuel companies are more often intentionally designing systems to burn the greatest amount of fuel their systems can get away with. Again, not all fuel companies are doing this, only the unethical ones are. Still, there is a great amount of ignorance in heating system design. HVAC sales engineers (like myself - see my resume at my website) are few and far between. Companies will pay great money to acquire a competent sales engineer. Conversely, HVAC companies aren't looking for them because they know it is a futile search.
Residential building owners are the most taken advantage of by companies through deliberate and unintended shoddy heating system design, installation and service. This is true because homeowners do not have the desire to learn about their heating system, nor the time to get over the learning curve. Therefore, they do not know the right questions to ask of a GC, HVAC or fuel company. They often are meticulous in scheduling the annual cleaning/inspection of their heating system, yet lack the important knowledge to determine if the cleaning was done right. They will never know if the system was designed and installed right and if the technicians who have worked on it through the years knew what they were doing. Any incompetence along the lifespan of the system, from design to the last service call before the system is replaced, will cost the homeowner more money. Mostly, homeowners are oblivious to the extent they are being ripped off!
Here's a rip-off scenario of a different kind. People think they have to spend ,000 to save a grand a year in fuel cost! They are lead to believe this routinely by energy auditing "professionals". In a blog post to come I will explain how "energy auditing" firms are duping their clients into believing they need some kind of sophisticated analysis to determine how their client can save money on fuel, and that they need high tech HVAC equipment to save money on energy costs. This is a huge scam, considering the energy auditor will charge tens of thousands of dollars to evaluate their building before any energy efficiency measures are carried out. They fly under the flag of the monetary incentives for the building owner provided for in the The American Recovery and Reinvestment Act of 2009 - The "Economic Stimulus Package".
Recently, I was contacted (through a referring party who worked for the New Hampshire Public Utilities Commission) by a woman who had been a policymaker with the same state agency for 20 years. She inquired about converting 3 heating systems in 2 apartment buildings to higher efficiency gas-fired boilers, so she could do her part in reducing her carbon footprint and qualify for benefits under the U.S. "Stimulus Package". I told her the ramifications of changing her chimney-vented boilers to direct-vented types would be a costly endeavor, approaching ,000 apiece. I also told her that I could make her cast iron mid-efficiency FHW boilers burn as much as 15-30% less gas. Of course, she was all ears. She hired me for a couple of grand to install temperature modulation controls on the 3 boilers and make a few other modifications. The end result means she will spend about the same on fuel as the new technology high efficiency boilers would require, and she got these modifications for about ,000 less!
Commercial building owners are generally more required by job description to know important things like, the benefits of heat loss calculations, proper equipment output capacity and the steps required of technicians doing maintenance. This is not to say that commercial building owners are not somewhat in the dark, too. Not all commercial buildings are managed by people who are wise to HVAC technologies and the tricks-of-the-trade, shall we say. Nevertheless, commercial systems naturally consume greater amounts of fuel - the space to be heated is bigger than homes - and when they burn inefficiently the wasted fuel is also greater than that wasted in residential applications. Therefore, it is more imperative for commercial building owners to make sure they are getting the correct answers from their HVAC professionals.
Like the fox that guards the hen house, your fuel company is not unlike the fox. The more fuel your heating system uses, the more money you pay your fuel supplier. It's logical then to believe that the greatest amount of fuel they can sell you is what they endeavor to sell you. Like the fox scheming to eat the hens, fuel companies can and do design and service heating systems in ways that demand the burner burns more fuel than is otherwise necessary to heat your building. All they have to do is skip the heat loss calculation and pick an inefficient, oversized American-made boiler and sell it to you. You trust them and are confident that the new boiler will heat your house reliably. You hope you will save money on fuel, but at least it won't break down soon. Unfortunately, the fuel company salesman didn't tell you the new boiler is a single-pass flue design and has a gross stack temperature of 450 degrees. He also didn't tell you that you could have bought a European boiler with a triple-pass heat exchanger and resulting 300 degree gross stack temperature. He also didn't offer to sell you a temperature modulation control and an indirect-fired water heater. Instead, you got a boiler with a "tankless" coil (for domestic hot water) that requires the boiler maintain constant temperature 24/7 all year long. All the while, heat constantly escapes up the chimney into the atmosphere.
What if you are considering the purchase of a building? You walk-through the building and make note of as much detail as you are able to in a limited number of walk-throughs. You calculate the cost of things like paint, landscaping, obvious mechanical systems repairs and the like, but you most likely know very little about heating technology, but do you know how fuel efficient, or inefficient the heating system is? You can ask what the past fuel costs have been, but without knowing what the infiltration rate of the building is and how many BTUs are required to heat the building on the coldest day of the year, then you will not be able to make any educated conclusions about the heating system's efficiency and effectiveness. Therefore, you will not be able to accurately predict the cost to heat the building. If you buy the building you will find out in the first year what the heating system consumes in fuel, assuming the weather is typical winter weather.
Here are the mechanical reasons behind high fuel and electricity cost:
No one did a heat loss calculation before the heating system was installed and they guessed at the BTU capacity of the heating appliance (boiler or furnace) and/or the radiation (baseboard or duct and diffusers sizes) capacity was undersized. A boiler/furnace that is too big, as discussed, will short cycle and consume too much fuel like city driving. A boiler or furnace that is too small will not adequately heat the building, the conditioned space will not reach the desired temperature so the thermostat will never be satisfied and the boiler/furnace will never shut off - and burn too much fuel.
The boiler or furnace was installed incorrectly. The supply and return piping was the wrong diameter and/or the ducts and/or diffusers were the incorrect size.
The number of installed zones (each zone has a thermostat, so count tally them up and that's the number of zones in your system) was either too many or, less likely to cause excessive fuel consumption, too few.
The installed zone(s) had too much radiation capacity connected to it/them. Too much baseboard radiation on a forced hot water zone will cause a heat imbalance in the building and hot and cold spots will ensue. The solution is to split the zone into more "loops".
Ducts or pipes were not insulated in unconditioned spaces. You really don't want to inadvertently heat basements, attics, crawl spaces and the like, therefore, the ducts or pipes need to be insulated. Ducts also need to be sealed to prevent air escape.
The installer did not set up the combustion process to achieve the carbon dioxide, oxygen, smoke, gross stack temperature and draft levels that the manufacturer intended. Too high a stack temperature (too much negative draft in the smoke pipe) means too much heat is escaping up the chimney. Too low a CO2 percentage of flue gas means the fuel isn't being completely combusted (at least as much as is possible with the equipment). Too much smoke in a smoke test means the boiler or furnace will "soot up" quickly. An 1/8" of soot is equivalent to an inch of fiberglass insulation. You don't want insulation on the heat exchanger, otherwise the heat generated by combustion will not transfer into the heating medium - air or water - and the heat will go up the chimney in excessive stack temperature.
In the case of oil burners and power gas burners, if the burner output capacity in BTUs was not matched to the boiler/furnace "input capacity" then the burner will either short cycle (burner output too great), or the burner will never shut off (burner output too little).
The installing contractor selected a boiler with a temperature limit control that maintains temperature in the boiler that is too great for the application. The installer incorrectly set the temperature limits in the aquastat (boiler) or fan and limit control (furnace). Too much fuel and electricity will be consumed as a result.
The wrong flow capacity circulators were selected and installed in the forced hot water system. Not enough heat is transferred to the space (the burner will short cycle) or electric consumption will be too great.
The burner - gas or oil - metering device (orifices with gas; nozzle with oil) was incorrectly selected, which usually means the wrong boiler/furnace or burner was incorrectly selected and installed. Almost always, the manufacturer of the heating equipment charges their engineering department with the task of Research and Development to determine what nozzle of orifice(s) are correct and set up the burners to include the correct ones with their burner/boiler or furnace. Nevertheless, incompetence can get in the way and that is often messed up in the field.
The installer did not set the correct metering rate for the requisite gas input rate for the burner. This means that he did not adjust the "manifold pressure" for the gas after the gas valve on the gas burner. With today's high efficiency, multi-stage firing burners, this is a very technical set up feature that absolutely must be done. In certain cases, a gas explosion can result if the manifold pressure in each firing stage is not set correctly. This must always be done in the field after complete system installation.
The installer did not follow the manufacturer's installation and/or service instructions to the letter. Too much fuel or electricity will be consumed, too much or too little heat will be generated, and/or a safety issue will result.
Water through pipes and/or air through ducts was not properly balanced, causing heating imbalance in the conditioned space and excessive electrical consumption by circulators and blowers.The bottom line is if the designer did not properly design the system, then:
Too much electricity and/or fuel will be consumed.
The system will most likely never work correctly.
The system can become a danger to people and property.
Consequential damage costs can result.
Civil litigation costs can be expected.
The installed cost of the system will not be accurately represented.
The environment will suffer.
The building owner will pay with his money, time and frustration level.The bottom line is if the installer did not properly install the system, then:
Too much electricity and/or fuel will be consumed.
The system will most likely never work correctly.
The system can become a danger to people and property.
Consequential damage costs can result.
Civil litigation costs can be expected.
The installed cost of the system will not be accurately represented.
The environment will suffer.
The building owner will pay with his money, time and frustration level.The bottom line is if the service technician did not properly service the system, then:
Too much electricity and/or fuel will be consumed.
The system will not work correctly until a technician who knows what he is doing fixes the problem(s).
The system can become a danger to people and property.
Consequential damage costs can result.
Civil litigation costs can be expected.
The service cost of the system will not be accurately represented and will always end up costing more.
The environment will suffer.
The building owner will pay with his money, time and frustration level.The bottom, bottom line is any of the above bottom lines can be combined and the result will be a veritable nightmare for the building owner. I see the outcome on a regular basis and this is why people hire me - to fix these screw-ups. At least 90% of my work is generated from the screw-ups of other HVAC designers, installers and service technicians. This is not to say that we don't all make mistakes. We do, I do. Some who make mistakes offer no solutions or apologies for their mistakes. I do.
So what can you do when you suspect that someone has made mistakes with the design, installation or service of your heating system, or any HVACR system in general? Contact me. This is why I offer design, installation, service, consulting and expert witness services in the Heating, Ventilation, Air Conditioning, Ventilation, Refrigeration, Humidity Control, Exhaust and other aspects of the "HVAC" realm. There's a huge market for it.
Here's what you need to do to prevent the mistakes from being made in the first place:
Research your prospective HVAC installing contractor's background - ask for references, his training history, employment history, his website, his specialization(s), if any.
Ask your installing contractor, or general contractor, who is responsible for the design of your system. If they say their parts supplier, tell them you are not interested. You must hire an installer who does his own designs. That way, if things go wrong he is solely responsible for the system shortcomings. In the worst case scenario, you do not want to have to sue multiple companies/individuals, or your legal bills will preclude your success.
Make sure you get a copy of the heat loss calculations...in their entirety! If they can't offer you a copy (this means they have not done the calculations in Wrightsoft, Elite, or an equipment manufacturer's proprietary software), then fire them before you hire them!
Ask your installing contractor to see his portfolio of past installations and the names and contact information of his customers with those systems. If he can't provide that information, then move on to the next installer who can.
Ensure that you speak directly with the installing contractor. If your general contractor/builder does not allow this...fire him before you hire him!
When you speak directly with the prospective installing HVAC contractor, make sure you discuss the type of fuel you intend to burn; the type of venting method you will be using (masonry chimney, high temperature metal chimney; sidewall/direct-vent, or "ventless") and the efficiency range (mid-efficiency or high-efficiency) of the equipment that you desire. Also, do some research on heating system types, product types, brand names, furnace and boiler material construction types (cast iron, steel or cast aluminum) and the approximate costs for each versus what your return on investment (ROI) will be for each.
Pick your installing contractor's brain for his reasons for selecting the types and brands of the equipment and materials who chooses to install. If his reasons don't sound quite right, then there is a red flag. Get other installer's opinions and recommendations and go with your gut feeling.
Tell your general contractor/builder that you want several alternate HVAC installer quotes...then go with your gut feeling on which one to select for your project.
Educate yourself as much as you can with all that you can stand to know about heating systems. "An Educated Consumer is Our Best Customer!" You've heard that slogan before. Be that educated consumer.
Never buy a system because it was the low bid! You virtually always get what you pay for. "Pay Now or Pay Later!" You've heard those cliché's as well.
Let me design your heating/HVACR system(s). Then you will know you covered all the important bases. I will provide you with a heat loss analysis, Bill Of Materials (estimate for every single part that your system(s) will be comprised of, down to the last screw and wire nut), Proposal with all the essential information and legalese, in an understandable presentation, and any and all product specifications that comprise your system.
If you don't hire me for your designs, estimates or proposals, then let me review those of your installing contractor so I can pinpoint any shortcomings.
If you live in my area of business, then consider me for the system installation and service.
If you hire someone else, then let me inspect his work...before you make the final payment to him! That way you will have leverage if he did something that is wrong and the system won't perform as intended. He will come back to fix a problem if he knows he will get paid when the problem is fixed.
Make sure that the installed system is inspected by the local Municipal mechanical inspector and/or the Fire Chief. But don't rely too heavily on the "rubber stamp of approval" from the inspector, as a good majority of inspectors have no idea what they are even looking at.
Check with your state's Public Utilities Commission to see if they prescribe and enforce energy efficiency measures and codes. You will be surprised how many installers do not know of or follow these prescribed codes and measures, or if they even exist.I could tell you volumes more about HVAC systems efficiency and safety, but that will have to be seen in past and future Blog postings. In the meantime, good luck and be educated!
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