There are three main reasons why your in-home Wi-Fi can reduce the speed of your broadband connection:
Interference from devices using the same Wi-Fi radio frequencies.
Congestion caused by accessing too many internet services on too many devices at the same time.
Only Wi-Fi weak signals being available in some parts of your house.
If the Wi-Fi checker app detects your Wi-Fi may be slowing down your broadband, you may want to try the following:
Move your router away from electrical devices: Halogen lamps, electrical dimmer switches, stereo or computer speakers, Christmas fairy lights, TVs and monitors and AC power cords have all been known to cause interference to broadband routers.Keep your router as far away as possible from other electrical devices as well as those which emit wireless signals such as baby monitors etc.
Move your router: The walls and furniture in your house act as an obstacle to the Wi-Fi radio frequencies. Ideally routers should be kept centrally within the home and placed on a table or shelf rather than on the floor.
Try restarting your wireless router: This may automatically select a less busy Wi-Fi radio frequency.
Check the instructions: Look at the instructions for the wireless router to see if it allows you manually to select a less busy Wi-Fi channel.
Try running the app again: Run the app again closer to your wireless router. If this improves performance, try using your devices in these locations.
Turn off your internet connected devices: Try turning some of your internet connected devices off and running the app again. If performance improves you may be suffering from congestion in your Wi-Fi network. More recent home routers are often able to better cope with congestion.
Make sure you're using the router correctly: Check the router instructions to confirm it is operating correctly and has a connection to your broadband provider. Many home routers now indicate this using a light on the front panel.
Consider upgrading: If your home router is several years old you could try using a more recent one which often has improved performance.
You may have a low broadband connection speed. Your broadband provider should be able to let you know what your connection speed is. If a better connection is available from your current or another broadband provider, you may want to consider upgrading to a higher speed connection.
Wi-Fi uses radio frequencies at 2.4 GHz and 5 GHz. These frequencies are used by your wireless home router and those in your neighbours' houses. In addition they are used by a wide range of devices including baby monitors, garage openers, cordless phones, microwave ovens, and so on. This means that interference can occur in these radio frequencies, which can reduce Wi-Fi performance.
The lower 2.4 GHz frequencies tend to be more effective indoors than the higher 5 GHz frequencies. However, the 5 GHz band can support higher speed connections and is usually less congested than the 2.4 GHz band.
Nearly all wireless in-home routers support the 2.4 GHz frequencies. The 2.4 and 5 GHz bands are increasingly being supported in new in-home routers.
The walls and furniture in your house act as an obstacle to the Wi-Fi radio frequencies. The greater the number of obstacles and distance between your home router and your devices the lower the likely level of the Wi-Fi signals which reduces its performance.
In addition to this, interference from other devices in your or your neighbours' houses is likely to change depending where you are in your house.