How to choose the optimal sump pump for your needs
Updated: Jul 23, 2021
There is a vast variety of sump pumps on the market and it might be confusing for a homeowner to analyze the cost/benefit ratio of a particular model.
Let’s analyze the factors that will help you in buying the optimal sump pump for your basement.
The Pedestal and the Submersible sump pumps are the two most common types used. There is also the Venturi principle sump pump, but it’s mostly used as a backup. (We will cover backup sump pumps in another article.)
Pedestal Sump Pump
The pedestal sump pump stands on the bottom of the sump basin but because of its size, the motor is partly above the basement floor. The impeller is located at the foot of the pedestal.
This type of pump usually uses a vertical float switch that is installed on top of the motor. The pumping range (when the motor has to switch ON or OFF) can be set by adjusting the sliding grommet on the float rod.
The compact impeller housing makes the pedestal sump pump suitable for shallow or very narrow sump pits.
The easy access to the switch mechanism and the ability to adjust the pumping range, makes this type of sump pump very easy to set up and maintain.
Pedestal sump pumps with more than 1/2 HP are uncommon in the market, and only the expensive models have an adequate cooling system for their motors.
Pros: Compact impeller housing, easy to access and maintain, economic, adjustable pumping range.
Cons: Power above 1/2Hp not available, poor motor cooling.
Submersible Sump Pump
The submersible sump pump is smaller than the pedestal pump. They are compact and designed to work underwater.
These characteristics make it possible to place the sump pump completely inside the sump basin and to comply with the sealed sump basin plumbing code required by most local authorities.
The electric motor is enclosed in a waterproof housing. A special oil insulates the electric motor and transfers the heat to the external surface. The fact that the motor is submerged into the water makes the cooling system of this type of sump pump undoubtedly effective.
In a very active system, the motor's effective cooling system is the key factor to avoid overheating. Motor overheating may lead to the draining process being disabled by thermal protection, or even worse, motor damage or fire if the pump has no thermal protection.
Submersible pumps are usually equipped with an integrated vertical float switch that, in most cases, does not allow adjustments to customize the pumping range.
A few sump pumps are equipped with a tether switch.
When buying a sump pump, check if the pump includes a float switch. If not, determine what is more cost-effective – buying a slightly more expensive pump with all the parts included, or buying a float switch separately.
For maintenance, the sump pump needs to be removed from the sump basin in most cases. Otherwise, the repair work has to be done in the very restricted space of the sump basin.
The market offers a large selection of models with a variety of horsepower.
This type of sump pump is more expensive than a pedestal pump.
Pros: Compact, cooling properties, sealed sump basins compatible, power range.
Cons: Pumping range not adjustable (in most cases,) not easy to access.
Thermoplastic, stainless-steel, cast iron, or a combination of these materials are used in the manufacturing of sump pumps.
A combination of materials is often used in the different parts of the sump pump. The switch case, motor, pump housing and base are parts that might be made from a combination of materials.
Mid-to-high quality sump pumps commonly have a plastic switch case, a stainless-steel motor housing, and a pump housing in cast iron. Professional grade sump pumps are usually completely in cast iron with a powder-coated epoxy finish.
The materials used determine the pump's durability and the heating transfer properties, but this can have a considerable impact on the price.
Cast iron is considered the most durable and best heat transferring material, and therefore it is the best choice for pump housing in very active systems.
However, the special plastic used in a thermoplastic sump pump makes it a valid choice to keep the purchase cost down. But this type of sump pump is only recommended for not very active systems.
There are two main types: Vertical and tether float switch. Both are consolidated systems with pros and cons.
Vertical Float Switch
The vertical float switch is the most common, and it’s usually integrated into the pump itself. (A pump that integrates the switch is often called an Automatic Sump Pump.)
The vertical float switch is generally the only option used in high-end residential sump pumps.
How it works:
A floater slides onto a rod, and when the water level rises the floater pushes the lever of the switch up to engage the pump. When the water level drops, the floater goes down again, and the rod pulls the switch lever into the OFF position.
The smaller overall dimensions enable better optimization of the available space enabling the use of multiple pumps without big space constraints.
The switch replacement (if integrated in the sump pump) might be difficult. It might involve sump pump removal and, in some cases, it might even require sump pump replacement.
Tether Float Switch
The tether float switch is usually not integrated into the sump pump.
How it works:
The floater is a sealed, waterproofed body containing the switch mechanism. The cord of this mechanism is fixed onto the pump at a specific length to determine the pumping range. When the floater is in a vertical position (wire up, floater body down), the switch is in the OFF position and the motor is not engaged. When the water level rises the floater also rises until it reaches the horizontal position. The switch is then triggered and the pump engaged. When the water level drops, the float goes back into its vertical position again and the pump’s motor stops.
The tether float switch is usually a separate component that is easy to replace without the need of removing the pump in most cases.
It needs a rather large portion of the sump basin to operate correctly..
The market offers a power range between 1/4HP and 1HP.
Multiple factors need to be considered related to power.
The first aspect to consider is that generally the power is directly related to the pump's flow rate. The flow rate, in simple terms, is the amount of water the pump is capable of moving in a specific time frame. It is true that the more powerful the motor, the better, but we also need to consider the noise emitted and the related operating energy costs.
A good quality sump pump won’t be very noisy itself, but the water being pumped does make a noise. Thus, another aspect to take into consideration is that the faster the pump drains, the noisier the draining will be. However, the sound of the sump pump draining might give you peace of mind because it is a sign that the pump is working and protecting your basement. Just remember that sump pump and water draining noise might compromise the quiet and peace you want when relaxing in your finished basement.
Regarding the energy aspect, we need to consider the inrush current (also known as the switch–on surge) that affects all electrical motors. It can draw up to 20 times the normal current for the initial half-cycle of the motor and 4 to 8 times for a few seconds. So, the more powerful the pump, the more inrush current will be drawn. In a very active system, this will influence the energy bill negatively.
In a moderate to very active system, a wise solution could be to install two sump pumps if quiet operation and energy efficiency are priorities. A small pump for the standard cycle uses during low to medium activity, and a second, more powerful pump during medium to high activity such as spring when the snow melts.
In most cases, however, a 1/3Hp pump is more than enough. We will discuss how to choose a motor with the right power in another article.
Pros: High flow rate, fast drain.
Cons: Big dimension, produce noise, high operating energy costs.
Pros: Compact dimension, quiet operation, low operating energy costs.
Cons: Low flow rate, slow drain.
The pump, being an electrical power product, must be approved by an accredited certification or evaluation agency. Check this link to view the recognized, approved marks: https://esasafe.com/electrical-products/recognized-certification-marks/