HVAC systems are characterized by their variety, and they can be designed to meet any application. When comparing these systems with each other, it is important to note that no option can be considered better than the rest 100% of the time - the best option is that which meets your HVAC requirements and budget, while adhering to any applicable standards and construction codes.
Of course, energy efficiency is a highly desirable feature in any HVAC installation. Automation is also highly beneficial, making HVAC systems easier to manage while further improving their energy efficiency. This article will provide an overview of the main types of HVAC systems available, including the best practices for each case.
Hot Water Radiators
Radiator heating systems can be built to use either hot water or steam. Hot water is now the most common option, especially in new buildings, where it allows the boiler to be placed on a bulkhead near the roof to minimize the length of the flue. Steam systems are more common where Consolidated Edison provides the district steam service, or in very old buildings where the cost of upgrading to hot water would be prohibitive.
This is one of the oldest heating configurations used in New York, dating back to the pre-war era. However, this does not imply that radiator-based heating is inefficient; with a modern high-efficiency boiler, radiators can match or even surpass the efficiency of newer heating systems. Radiators are characterized by their silent operation, since they don’t use air ducts and dampers, which also minimizes the spread of mold spores and other air pollutants. Just keep in mind that radiators are exclusively for heating, so a separate installation is required for air conditioning. Packaged terminal air conditioners (PTACs) are a common option in older buildings, since they are self-contained and do not require hydronic piping or refrigerant lines.
If you are dealing with an existing installation and plan to upgrade the boiler, additional upgrades may be required for radiators, piping and chimney:
Repairing leaky radiators Reparation can be very difficult if the existing radiators have sections with threaded connections, and you may have to replace them completely. However, more recent models use push-in connections that can be sealed.
Upgrading chimneys:Old chimneys are not always capable of handling the flue gases of modern boilers, and if this is the case you must upgrade them with a stainless steel liner. Otherwise, acidic compounds can build up inside the chimney, causing an eventual collapse.
Piping upgrades and reparations Some older buildings suffer from leaks due to decades of corrosion, especially in the return lines carrying condensed water in steam-based systems.
Boilers can often be upgraded and downsized: Heating systems were generally oversized in the pre-war era, since they were calculated based on the building’s heating load with open windows. Downsizing provides additional energy savings beyond those achieved with a higher unit efficiency.
Steam radiators can be an attractive option if you are located in a district where Consolidated Edison provides steam as a utility service, since you can avoid the upfront investment in a boiler. The Con Edison steam service area covers the area from 96th Street to the southern end of Manhattan. Keep in mind that steam-based heating systems come in two main configurations:
- Two-pipe systems have a supply line for steam and a return line for condensed water.
- Single-pipe systems provide steam and retrieve hot water through the same pipe - this is possible because steam rises and water flows down.
Steam radiators can also be upgraded to use hot water, but there are special considerations. In old buildings, the cost can be extremely high.
The piping may require significant changes:Conversion to hot water may be impractical for single-pipe systems, since all radiators must be modified and return piping must be installed from zero throughout the property.
A pump must be added Unlike steam, hot water does not rise through piping by itself.