Benefits of Energy Efficiency in Pre-War Apartments

Energy efficiency is beneficial for any building, reducing monthly operating costs and contributing to environmental sustainability. However, in the case of pre-war apartments there are also many practical benefits: these apartments have very old installations and performance problems are less likely if the load is minimized.

As the name implies, pre-war apartments are those built before World War II, when engineering practices were very different from today. A key difference is that materials were much more expensive a century ago, while labor costs were very low. Therefore, it made sense to make very robust and long-lasting buildings, and remodeling was a less common concept. This trend has now reversed: materials are much cheaper, but labor costs have increased dramatically, especially in a place like New York City. Therefore, modern buildings are designed for quick construction and are therefore easier to renovate.

Electrical installation in a modern apartment is very easy as there are usually many empty spaces within the walls, ceilings and floors. On the other hand, pre-war apartments were not designed to be dismantled easily, with monolithic floors and walls that are very difficult to break down to install ducts. Not only is this time-consuming and expensive, it can also ruin the appearance of a pre-war apartment unless the owner has a high enough budget to restore the original appearance.

Modern household appliances with old electrical installations

The electrical wiring of a pre-war apartment often cannot handle the load produced by modern appliances, especially air conditioners. However, although society used fewer electrical devices 80 years ago, these were also much less efficient devices. As a result, it is possible to use more electrical equipment in a pre-war apartment if the equipment is selected as efficiently as possible.

Another recommendation is to use 220 volt appliances whenever possible, instead of 110V. Remember that electrical wiring is not sized based on power, but rather on current – ​​if the voltage is doubled, the current drops by half, even when the power consumed by the device remains the same.

It's true that energy-efficient devices come with a higher price tag, but using standard-efficiency appliances will likely require an electrical wiring upgrade, and in many cases this is a more expensive option. Opting for energy efficiency is better, reducing energy bills in the long term without the risk of ruining the small details of a pre-war apartment.

Suppose a pre-war apartment requires air conditioning with a capacity of 12,000 BTU/hour (1 ton of refrigeration). If a conventional window-type unit or a packaged terminal air conditioner (PTAC) is used, the unit will likely consume about 1,000 W. If the apartment is using ten 60 W incandescent bulbs, the total air conditioning and heating load is 1,600 W. However, consider an alternative approach based on energy efficiency:

• The 60-watt incandescent bulbs are replaced by 10-watt LED bulbs, reducing their total load from 600 W to 100 W.
• For air conditioning, a ductless mini-split system is used, with a Seasonal Energy Efficiency Index (SEER) of 28. If its capacity is 12,000 BTU/hour, its average energy consumption will be 429 W.

In this case, the new total lighting and air conditioning load would be 529 W, which is less than the previous lighting load – 600 W. In this case, the pre-war apartment circuit would have no problem accommodating air conditioning, since that the load is actually smaller.

Of course, the performance of the building envelope is also important. Owners of pre-war apartments should check the building envelope for air leaks, which can cause extra heat gain during the summer and additional load on air conditioning systems.

Equipment selection tips for pre-war apartments

Many pre-war apartments have incandescent lighting and their warm, natural glow is part of the ambience. LED lighting is often criticized for its “artificial” lighting effect, but this is not a common feature of all LED lamps. The following guidelines are recommended to preserve the glowing effect after a lighting upgrade:

• LED bulbs should be a warm white color. In terms of technical specifications, this means they must have a correlated color temperature (CCT) of less than 3000 K.
• Their color rendering index (CRI) should be as high as possible to mimic the natural lighting effect of incandescent bulbs. The highest CRI value is 100, and only incandescent and halogen bulbs can reach it. However, mainstream LED bulbs offer CRI values ​​above 90. Most commercial LED bulbs have a CRI above 80, while low-quality products may have values ​​in the 60s or 70s and are not recommended.

In general, appliances with the ENERGY STAR label are recommended. They have undergone extensive testing by the US Department of Energy and the US Department of Environmental Protection, so energy efficiency is guaranteed.

When it comes to space heating, space cooling and domestic hot water, the following table can help you select equipment with the lowest energy footprint:

In the case of heating appliances, consider that most systems in New York City use natural gas, heating oil, or district steam. However, heat pumps are also an economical option for homeowners who want to minimize the use of fossil fuels. Electric resistance heaters are generally not recommended because of their high energy consumption and also because they can overheat old electrical wiring in pre-war apartments. For a given heating output, a heat pump generally consumes 2 to 4 times less electricity than a resistance heater.

Benefits of energy efficiency for the entire building

Another advantage of energy-efficient pre-war apartments is that the savings add up to entire buildings. If many pre-war apartments in a condominium implement energy efficiency, it is less likely that the property management company will have to update the transformer, electrical service entrance and common wiring. These expenses are often shared between occupants, so avoiding them provides a common benefit.

Final Recommendations

As with any building upgrade, professional engineering advice is highly recommended before making decisions. Property management companies can identify the most promising measures with an energy audit and may be eligible for cash incentives from Con Edison. In general, the best results can be achieved with LED lighting, high-efficiency heating and cooling, and ENERGY STAR appliances.