In recent years, a large diversity of network-enabled devices have been widely prevalent in home environment. With the prevalence of such devices, wireless home networks enable monitoring and control applications for home user comfort and efficient home management. In the home network, alarm signals must be delivered in real-time to the residents or to the emergency services and some home control applications require the response time to be on the order of a few hundred milliseconds for optimal user experience. Most recently, ZigBee has emerged as one of the most promising technologies for wireless home networking because it is targeted at applications that require a low data rate and long battery life, which are also the features of home network applications. However, its usage in close proximity to Wireless Local Area Networks (WLANs) introduces coexistence problems, resulting in failing to fulfil the response time required by the home control applications. To overcome this problem, we propose to control the WLAN traffic when there exist ongoing ZigBee transmissions and the maximum tolerable delay is not met due to the WLAN interference. We aim to guarantee that the delay experienced by ZigBee sensors (especially, for alarm signals) does not exceed the maximum tolerable delay, while maintaining as high throughput as possible in the WLANs. The simulation results demonstrate that our proposed algorithm can enhance the delay performance of ZigBee networks by mitigating the effect of WLAN interference and improve the throughput in the WLANs.