Everything About a Hot Water Heating System

Hot water heating systems are an integral part of our heritage and are still found and efficiently used in most centennial houses in Quebec. The main reason they’re not as common nowadays is that installation costs are steeper than that of other heating systems, which makes some homeowners reluctant. In older buildings, it’s rather tempting to opt for electric baseboard heaters. However, if you’ve already got this type of heating system installed, consider all your options before making a final decision. And for those who're looking for an efficient system to improve the overall level of comfort in their home, hot water heating may be the best choice for years to come. 

Hot water heating has proved itself over the years and is still improving. The process is far from archaic - in fact, newer systems are more than 90% efficient. Using hot water is by far the best way to distribute heat in a residential property. Hot water heating is convenient, durable, noiseless, economical, clean, and eco-friendly, despite it being older than Grandma. 

This system is both cozy and tireless and can be modernized to meet the needs of new generations. 

How Does Hot Water Heating Work?

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Hot water heating allows you to heat a dwelling by means of a boiler that sends heated water to your heating units (radiators, baseboard heaters, floor heating, etc.). While its use is relatively simple, the benefits are invaluable!

This type of system is supplied by a heat-transfer fluid, basically, water, which will increase the temperature of the electric boiler, powered by either natural gas, propane, or oil.  

How does the water circulate?

The hot water boiler is connected to the various heating appliances by a piping system, and one or more circulators feed hot water through the house directly into radiators, convectors, baseboard heaters, or underfloor heating systems. Thus, providing the entire home with a comfortable warmth. 

The pipes running between the boiler and the radiators enable hot water to circulate, thereby releasing a gentle, even heat. Note that the water in these pipes stays hot for a long time. During the January 1998 North American ice storm, some radiators remained hot and efficient despite a two-day power outage.

When the water cools down, it's pumped back into the boiler to be reheated, or done so merely by gravity (the boiler is usually located in a basement), and the cycle repeats itself.

Now, installation requires a double-acting hydraulic cylinder, one to deliver water to the heating appliances, and the other used to return the water to the heat generator. It’s a closed circuit, so it’s always the same water that circulates.

Heating Unlike Any Other

Rather than heating the room itself, the hydronic system heats the objects using radiation, resulting in a more constant flow compared to a forced air system.

As the water circulates through the pipes, it’ll first heat the walls of the units using convection. Then, the heat will flow through the metal structure by way of conduction. Finally, the warm air will diffuse by radiation, just like the sun's rays warm floors, walls, furniture, and even the individuals in a room. The majority of the energy will be dispersed as such.

Designed to provide maximum efficiency as well as even heat, various radiators are equipped with numerous fins, tubes or blades. The "accordion" shape, a tribute to its predecessor, is still very much present in today's systems since it significantly increases the heat exchange areas.

Small- and Large-Scale Heating

Contrary to popular belief, hydronic heating can be installed in all types of buildings, whether it be a residential home, a multi-housing unit, a commercial space, or an industrial building.

With individual heating, a boiler supplies heat to all the rooms in the house or apartment. With collective heating, the boiler distributes heat to all the apartments within a complex. This approach can be developed on a large scale, as there are also heat networks for districts or cities.

Beneficial Features of Hydronic Heating

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When the winter cold hits, we tend to give in to the idea of using one of the most efficient heating systems, with numerous advantages. If you want to benefit from uniform ambient heat throughout your home, hot water heating is definitely the way to go!

Uniform Heating Solution for Maximum Comfort

As opposed to an electric heating system, or other various appliances that diffuse heat independently, a centralized hot water heating system functions around a closed circuit to provide constant and uniform warmth in every room.

Since it heats objects (floors, walls, furniture, etc.) rather than the ambient air, this unique system eliminates hot, dry drafts, and the discomfort of low or high levels of humidity, as well as temperature variations. Instead, heat is released gradually, where and when it's needed, to ensure unparalleled thermal comfort.

Also, it should be noted that the temperature of the water flowing through the pipes isn’t sufficiently warm to cause burns from touching the radiators and other appliances.

Clean Air for a Healthier Home

As previously mentioned, a hot water heating system doesn’t cause air displacement. It heats up mass rather than ambient air and doesn’t contribute to dust, pollutants, and allergens moving through the home, as do forced-air central heating systems and older ventilation systems.

Therefore, this makes it a great option for anyone suffering from allergies or chronic respiratory diseases, such as asthma, sleep apnea, or others.

An Eco-Friendly System

Not only is a hot water heating a safe option for residents, but it's also an eco-friendly option. Given that it uses the same water supply as it circulates in the pipes, this clever system proves to be very green. After all, water is a renewable but precious resource. A hot water system works in such a way that its supply can be recycled over and over again, thereby avoiding wasting the planet's resources.

As a bonus, the hot water heating system is both clean and eco-friendly, as it doesn’t release greenhouse gas emissions or pollutants into the atmosphere while in operation.

Noiseless Performance

One other advantage that makes hot water heating worth mentioning is that it makes virtually no noise. If properly calibrated, it's very quiet, if not inaudible, and provides a pleasant tranquillity.

Cost-Efficient System

Compared to other heating systems, installing a hot water system may sound expensive. However, compared to a traditional electric baseboard heating system, the costs associated with its use are lower, making it a long-term money-saver.

Hydronic heating evenly distributes and regulates the heat in the home. Simply maintaining the temperature with zero fluctuation reduces household energy consumption. This translates into big financial savings on utility bills.

To sum it up, regardless of the fact that it's remarkably durable, it's an excellent investment, since hot water heating is more cost-effective than the most popular heating systems. 

The Outstanding Effectiveness of Hot Water Heating

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While hot water heating systems are highly durable, a boiler's age speaks volumes about its efficiency. While an old oil boiler can convert 60% of the energy found in its fuel into heat, electric boilers are much more efficient, with 100% efficiency. Gas boiler efficiency varies between 80% and 95%.

To improve efficiency, besides changing your old boiler, you can retrofit your hot water heating system with an "indoor/outdoor" temperature controller, no matter how old it is. The controller monitors both indoor and outdoor temperatures to determine the ideal setting. This allows you to maintain a constant temperature, and save a lot of money compared to systems that overheat before shutting down.

Minimal Maintenance

Hot water heating systems have stood the test of time. If properly maintained, their operational life can easily exceed fifty or sixty years. Besides preserving the thermal comfort in your home, annual maintenance ensures the durability of your heating system. It's a simple and rarely expensive routine that can prevent many concerns.

Boiler and overall system cleaning and maintenance should be done by a professional technician. Below are the most important maintenance tasks to ensure the efficient performance of the hot water system:

• Make sure that the water level is set at an optimal level and that the air trapped in the pipes is cleared (oxygen contributes to the corrosion of some steel pipes and hinders the water flow);

• Clean the combustion chamber to ensure the necessary amount of heat is produced for the system to properly function;

• Ensure that the water pressure is good and constant;

• If needed, lubricate the water pump for a good water flow;

• Analyze the contamination level of the water and replace it if necessary;

• For oil and gas boilers, check whether the boiler is burning properly and if it’s safely vented (electric boilers require very little maintenance).

Lastly, professionals recommend bleeding your heating system once a year by withdrawing two to three cups of water, to avoid damaging the pipes.

Be careful!

Are parts of the boiler or pipes running hot? This could be a sign that there's an insulation problem, and thus a heat loss issue.

Are the pumps or valves leaking? Rapidly ensuring that the pipes are watertight is super important. Wall leaks are not common since the main connection points are near the appliances and boiler. However, water leaks under the appliances can damage floors and even the building’s structure and cause utility bills to skyrocket.

A Good Pipe

A hot water heating system is made up of galvanized steel pipes (or copper pipes for older models) that absolutely need to be maintained. The two main problems are pipe scaling and corrosion. 

Scaling is the result of waste matter found in drinking water, especially when it contains a lot of limescale. When heat and pressure are applied, scale tends to crystallize on the metal walls of the pipe. As a result, water flow rates are reduced and heat transfer is delayed, causing energy consumption to increase by as much as 40%. In the worst cases, the piping can occasionally rupture. 

Unfortunately, corrosion stems from the fact that the majority of pipes used today are made of galvanized steel. If not insulated, they're prone to corrosion in unheated areas of the home.

Different Hot Water Heating Systems

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If the oil boiler is on the verge of extinction, the hydronic electric heating system is the perfect alternative due to its excellent efficiency and because it requires very little maintenance. On the other hand, gas boilers maintain their title as the most economic and eco-friendly option. 

Provided the boiler is large enough, hot water offers quite an array of possibilities: Enjoy hot water for various household needs and tasks, easily heat an add-on room, veranda, or sunroom, or simply add a heated floor or a towel warmer, or heat your pool water... Basically, let your imagination run free!

These features are obviously broken down into different options. To make the right choice, it's best to know how to distinguish the various characteristics and features.

Types of Power Supplies

The main methods of powering hot water heating systems are fuel (wood or gas) and electricity. Note that hybrid or dual-energy boilers enable the use of two energies during very cold spells, which allows you to benefit from favourable rates from Hydro-Québec.

Electric boilers are easy to install, neat and compact, thus making them ideal in residential homes and commercial spaces. They're always reliable and efficient and have a virtually unrestricted lifespan.

Natural gas boilers are amongst the most energy-efficient heating appliances on the market. On top of that, they produce very little pollution. And, yearly maintenance guarantees their efficiency over the years.

Types of Systems

To create a water flow, two types of hot water systems are used: gravity-fed and forced water systems.

Gravity-fed system

Gravity-fed systems don't rely on a pump to function properly. Due to the ingenuity of this system, water flows through the house to heat the various rooms, before it's heated again. This is accomplished by exploiting the difference in density between the supply water and the return water.

When water is heated, it expands and its density drops. In turn, it causes water to rise in the pipes. The energy is then distributed to the various units of a room by means of baseboard heaters and other devices, thereby lowering the temperature of the water. As it cools, the water contracts causing its density to increase. It then naturally plunges towards the boiler to allow the cycle to repeat itself. Having an expansion tank means you can safely manage the increasing volume of the water once it’s been heated.

Since the driving force of gravity-fed systems isn’t as strong as that of forced air systems, it’s offset by the larger piping.

There's a growing trend towards replacing the gravity-fed system with the forced air system. Although efforts have been made to overcome the slower driving force through larger pipe sizes, the water flow remains slower and the temperature fluctuations between heating cycles are still noticeable. This type of system also negates the possibility of using the basement, unless you aren't bothered by cold floors. In fact, since the hot water is less dense, it automatically rises above the level of the boiler and prevents the temperature from being evenly distributed. 

Forced air heating system

Forced air heating units use a pump system to maintain water flow. They're grouped into four distinct categories based on their individual piping.

A unique pipe runs through the building to supply all the heating appliances (radiators, baseboard heaters, convectors, etc.). The hot water needs to flow through each radiator, thus losing its heat according to the power of the appliance it feeds, before returning to the boiler. 

While this system is limited in capacity, it's relatively inexpensive to install and duct insulation becomes unnecessary because the piping is located near the floor. However, it's impossible to regulate the temperature of one unit without affecting the others.

Loop systems are most often used in small buildings or as a sub-circuit of a larger system.

With this system, every heating appliance is linked to one main piping supply. As opposed to the loop system, each heating unit can be regulated by means of a control valve. 

This type of system has two separate piping networks. The first one allows hot water to flow toward heating units. Once the water has cooled down, the second pipe draws the water back to the boiler to reheat it. However, it requires each unit to have a control valve, which makes it difficult to regulate.

This system is similar to the previous one, but the return flow is via an additional pipe. The cooled water, therefore, returns directly to the boiler along the supply pipe. However, it's easier to balance, allowing each individual unit to be supplied with water at the same temperature.   

Whether you're in the middle of a renovation project or looking to cut back on your utility bills, choosing your heating system carefully is key. After all, you can get a high-performance system that offers maximum comfort at a reasonable cost!