Here's a draft you can adapt:

Subject: Urgent repair request – no heating at [property address] since [date]

Dear [Landlord's name],

I hope you're well. I'm writing to follow up on the heating issue at [property address], which was first reported on [date] — three weeks ago. As the weather has turned colder, the lack of heating has made the property increasingly difficult to live in, and I'm concerned about the impact on the property itself (pipes, damp) as well as my health.

I completely understand that repairs take time to arrange, and I'm happy to be flexible with access — please let me know what days and times work for you or your contractor, and I'll make sure someone is available.

That said, I'd be grateful if the repair could be completed by [specific date, e.g., one week from today]. If it would help, I'm happy to obtain quotes from local heating engineers to speed things up.

If I don't hear back by [date], I'll need to explore my options with [local housing authority / tenancy advice service], as I'm sure you'll agree that a property without heating isn't safe or habitable. I'd much rather resolve this directly with you, so I hope we can get this sorted quickly.

Please confirm when the repair is scheduled. Thank you for your attention to this.

Kind regards, [Your name] [Your address / unit number] [Phone number] [Email address]

A few tips:

• Send it in writing (email or letter) so you have a record — keep a copy of everything.

• Check your local rules: many places require landlords to provide heating, and some have specific timeframes (e.g., 24 hours for essential repairs in winter). Your local tenant rights organization can confirm.

• Document the cold: photos of a thermometer reading, screenshots of texts you sent, and a log of dates help if you need to escalate later.

• Stay calm and cooperative in tone — as you said, you want the repair, not a fight. Landlords respond better when they feel you're reasonable.

If the landlord still doesn't respond after your deadline, you can contact your local council's environmental health team or a tenants' advice service (like Citizens Advice in the UK, or a local tenant union elsewhere) — they can inspect the property and formally require the repair.

Would you like me to adjust the tone (firmer or softer) or tailor it to a specific country's tenant laws?

Here's a generic, fully-typed debounce hook:

import { useEffect, useState } from 'react';

/**
 * Returns a debounced copy of `value` that only updates after `delay` ms
 * have passed without the value changing. The pending timeout is cancelled
 * on unmount (and whenever `value` or `delay` changes).
 */
function useDebounce<T>(value: T, delay: number): T {
  const [debouncedValue, setDebouncedValue] = useState<T>(value);

  useEffect(() => {
    // `ReturnType<typeof setTimeout>` keeps this correct in both
    // browser (number) and Node (Timeout) typings.
    const timer: ReturnType<typeof setTimeout> = setTimeout(() => {
      setDebouncedValue(value);
    }, delay);

    // Cleanup runs on unmount and before the next effect,
    // cancelling any pending update.
    return () => {
      clearTimeout(timer);
    };
  }, [value, delay]);

  return debouncedValue;
}

export default useDebounce;

Usage example:

import { useEffect, useState } from 'react';
import useDebounce from './useDebounce';

function Search() {
  const [query, setQuery] = useState('');
  const debouncedQuery = useDebounce(query, 300);

  useEffect(() => {
    if (!debouncedQuery) return;
    // Only fires 300ms after the user stops typing
    fetch(`/api/search?q=${debouncedQuery}`)
      .then((res) => res.json())
      .then(setResults);
  }, [debouncedQuery]);

  return (
    <input
      value={query}
      onChange={(e) => setQuery(e.target.value)}
      placeholder="Search..."
    />
  );
}

How it works:

• The generic <T> means it works with strings, numbers, objects, etc., and the return type matches the input type automatically.

• Each time value (or delay) changes, the effect re-runs: the cleanup function calls clearTimeout, cancelling the previous pending update, and a fresh timer is started — that's the "debounce."

• When the component unmounts, React runs the cleanup one last time, so the timeout is cancelled and setState is never called on an unmounted component (avoiding the React warning and memory leaks).

Assuming “99% accurate” means 99% sensitivity and 99% specificity:

• (P(\text{use}) = 0.5\% = 0.005)

• (P(+ \mid \text{use}) = 0.99)

• (P(+ \mid \text{no use}) = 0.01)

By Bayes’ theorem:

[ P(\text{use}\mid +)= \frac{0.99(0.005)}{0.99(0.005)+0.01(0.995)} = \frac{0.00495}{0.0149} \approx 0.332 ]

So the probability is about 33%, not 99%.

Example with 100,000 people: only 500 use the drug. Of those, about 495 test positive. But 99,500 do not use it, and 1% of them—about 995—falsely test positive. Among all 1,490 positive tests, only 495 are true users:

[ 495/1490 \approx 33\% ]

It surprises people because of base-rate neglect: they focus on the test being “99% accurate” and ignore that the drug use is rare. When a condition is rare, even a small false-positive rate applied to the huge non-user population produces more false positives than true positives.